STUDENT NO 21123303
33 39 49 33 70 40.9
Thursday, November 3, 2011
immunology course marks 2011
student TEST1 TEST2 PRAC1 PRAC2 Project CM
21110644 54 66 85 70 70 66.25
21001585 58 33 81 47 70 53.5
21001710 50 78 89 90 100 75.25
21141071 59 70 70 80 90 70.2
21008595 77 95 53 82 70 78.85
21108605 55 51 75 47 70 57.1
21008167 55 14 55 83 0 41.4
21014104 42 51 70 85 70 58.15
21014093 55 68 98 88 70 71.8
21001465 50 81 75 77 100 72.1
21113096 19 18 73 20 50 30.05
21103142 42 60 74 73 70 59.65
21123354 38 51 53 68 70 51.85
20908733 43 53 65 60 60 53.55
21107438 50 73 90 93 80 72.35
21141069 41 55 68 63 70 55.45
21120190 50 48 60 47 70 52.45
21014095 63 62 85 87 90 72.3
21014107 71 97 93 93 100 88.3
21004440 69 74 75 70 100 74.65
21009732 54 54 63 63 70 58.3
21014109 56 59 78 78 70 64.9
21005818 70 63 83 80 70 71.35
20902745 36 71 78 80 70 62.8
21108356 60 52 85 90 70 66.85
20906847 58 57 98 77 60 66.75
21130079 40 16 41 43 50 34.4
20936113 70 64 84 93 100 76.75
21109005 22 76 83 60 70 57.85
20905697 34 53 83 55 60 52.8
21123303 33 39 49 33 0 33.9
20907389 39 47 73 60 60 51.75
21111318 57 60 53 63 70 59.5
20900883 52 58 73 70 90 63.45
21013928 74 68 80 95 90 77.85
21103921 49 66 71 47 70 59.2
21017854 57 57 76 63 70 62.05
20907165 21 36 73 37 50 38.6
21014097 55 61 98 53 70 64.45
20903040 50 65 89 50 70 62.35
21008877 52 41 75 83 80 59.6
21104720 51 46 76 73 80 59.45
20900920 35 62 34 8 0 35.4
20920886 47 64 83 53 60 59.7
21110353 31 47 73 67 70 51.4
21139224 49 68 65 43 100 61.3
20924296 40 48 43 70 60 49.35
21011387 51 83 65 67 70 67
21000961 43 41 64 73 70 52.75
21030811 42 61 70 53 70 56.35
21110644 54 66 85 70 70 66.25
21001585 58 33 81 47 70 53.5
21001710 50 78 89 90 100 75.25
21141071 59 70 70 80 90 70.2
21008595 77 95 53 82 70 78.85
21108605 55 51 75 47 70 57.1
21008167 55 14 55 83 0 41.4
21014104 42 51 70 85 70 58.15
21014093 55 68 98 88 70 71.8
21001465 50 81 75 77 100 72.1
21113096 19 18 73 20 50 30.05
21103142 42 60 74 73 70 59.65
21123354 38 51 53 68 70 51.85
20908733 43 53 65 60 60 53.55
21107438 50 73 90 93 80 72.35
21141069 41 55 68 63 70 55.45
21120190 50 48 60 47 70 52.45
21014095 63 62 85 87 90 72.3
21014107 71 97 93 93 100 88.3
21004440 69 74 75 70 100 74.65
21009732 54 54 63 63 70 58.3
21014109 56 59 78 78 70 64.9
21005818 70 63 83 80 70 71.35
20902745 36 71 78 80 70 62.8
21108356 60 52 85 90 70 66.85
20906847 58 57 98 77 60 66.75
21130079 40 16 41 43 50 34.4
20936113 70 64 84 93 100 76.75
21109005 22 76 83 60 70 57.85
20905697 34 53 83 55 60 52.8
21123303 33 39 49 33 0 33.9
20907389 39 47 73 60 60 51.75
21111318 57 60 53 63 70 59.5
20900883 52 58 73 70 90 63.45
21013928 74 68 80 95 90 77.85
21103921 49 66 71 47 70 59.2
21017854 57 57 76 63 70 62.05
20907165 21 36 73 37 50 38.6
21014097 55 61 98 53 70 64.45
20903040 50 65 89 50 70 62.35
21008877 52 41 75 83 80 59.6
21104720 51 46 76 73 80 59.45
20900920 35 62 34 8 0 35.4
20920886 47 64 83 53 60 59.7
21110353 31 47 73 67 70 51.4
21139224 49 68 65 43 100 61.3
20924296 40 48 43 70 60 49.35
21011387 51 83 65 67 70 67
21000961 43 41 64 73 70 52.75
21030811 42 61 70 53 70 56.35
Wednesday, October 26, 2011
Monday, October 24, 2011
Wednesday, October 19, 2011
Functions of HLA antigens
Both MHC class I and II are involved in MHC restriction.
Both MHC class I and II are antigens targeted by the immune response in transplant rejection.
Some terms before we proceed:
Graft rejection refers to the recipients immune response rejecting the donor organ.
GVHD (graft versus host disease) refers to the transplanted organ mounting an immune response to the host's antigens. Sounds strange but GVHD is potentially fatal. That is why identification of Ag and Ab in both the recipient and donor is important.
HLA-A, HLA-B and HLA-DR are the main antigens targeted by the recipient, in graft rejection. If there are incompatibilities with these antigens, the feasibility of a successful transplant is low.
All MHC class II antigens are targets in GVHD.
Histocompatibility testing ideally should identify incompatibilities for both class I and class II. This will reduce the likelihood of both graft rejection and GVHD.
Both MHC class I and II are antigens targeted by the immune response in transplant rejection.
Some terms before we proceed:
Graft rejection refers to the recipients immune response rejecting the donor organ.
GVHD (graft versus host disease) refers to the transplanted organ mounting an immune response to the host's antigens. Sounds strange but GVHD is potentially fatal. That is why identification of Ag and Ab in both the recipient and donor is important.
HLA-A, HLA-B and HLA-DR are the main antigens targeted by the recipient, in graft rejection. If there are incompatibilities with these antigens, the feasibility of a successful transplant is low.
All MHC class II antigens are targets in GVHD.
Histocompatibility testing ideally should identify incompatibilities for both class I and class II. This will reduce the likelihood of both graft rejection and GVHD.
HLA and MHC
MHC is located on the short arm of chromosome 6. This locus codes for the HLA antigens that are found on various cells in the body. There are 3 classes of MHC.
MHC class I are found on platelets and all nucleated cells. examples of MHC class I are HLA-A, HLA-B and HLA-C.
MHC class II are found on macrophages, monocytes and lymphocytes. Examples are HLA-D, HLA-DP, HLA-DQ and HLA-DR.
Examples of MHC class III are C2, C4 and Factor B. (remember complement?)
We need to know the actual structures of MHC class I and II.
For each structure you need to know where antigen binds, and where CD4 or CD8 interacts. Remember that CD4 or CD8 are cell markers and are attached to cells, viz. TH and TC respectively. So do not draw just the cell marker; ensure that you draw the cell as well.
You need to know the names of each domain; these are not interchangeable and you will lose marks if they are labelled incorrectly.
Ag binds between alpha 1 and alpha 2, and CD8 interacts with alpha 3. (MHC class I)
Ag binds between alpha 1 and beta 1, and CD4 interacts with beta 2 (MHC class II)
MHC class I are found on platelets and all nucleated cells. examples of MHC class I are HLA-A, HLA-B and HLA-C.
MHC class II are found on macrophages, monocytes and lymphocytes. Examples are HLA-D, HLA-DP, HLA-DQ and HLA-DR.
Examples of MHC class III are C2, C4 and Factor B. (remember complement?)
We need to know the actual structures of MHC class I and II.
For each structure you need to know where antigen binds, and where CD4 or CD8 interacts. Remember that CD4 or CD8 are cell markers and are attached to cells, viz. TH and TC respectively. So do not draw just the cell marker; ensure that you draw the cell as well.
You need to know the names of each domain; these are not interchangeable and you will lose marks if they are labelled incorrectly.
Ag binds between alpha 1 and alpha 2, and CD8 interacts with alpha 3. (MHC class I)
Ag binds between alpha 1 and beta 1, and CD4 interacts with beta 2 (MHC class II)
Tuesday, October 18, 2011
TERMS in Ag Ab reactions
Titre refers to the concentration of a particular substance in a test tube.It is expressed by inverting the concentration of that substance. If the concentration of glucose is 1/16 in test tube no 4, the titre of test tube no 4 is 16.
A serial dilution is any dilution where the concentration decreases by the same quantity in each successive step.
double dilutions are a series of ½ dilutions. Each successive tube will ½ the amount of the original concentrated solution.
In any serological test done in the lab, we are looking for an unknown using a known. The known are the reagents that we use, usually commercialy available. The unknown is usually in the patients specimen, and can be either antigen or antibody.
Acute phase serum refers to specimen taken during the disease state, used to diagnose the disease.
Convalescent phase serum is taken after the disease has been treated, and can be used to determine if titre has decreased due to effective treatment.
Serum has no clotting factors present; usually specimen taken in brown top blood collection tube (with no anticoagulants)
Plasma has all clotting factors present; usually collected in purple top tube (containing anticoagulants)
Sterility is not an issue in serology as we are looking for presence of Ag or Ab. Any organisms present will not affect the results
Sensitivity refers to the ability of a serologicl test to identify the Ag or Ab in minute amounts. There will not be any false negative results due to the Ag or Ab being present in very small amounts.
Specificity refers to the ability of a serological test to identify the exact Ag or Ab being tested for. There are no cross reactions giving false positive results.
All serological tests have to be controlled. These controls are put up at the same time as the tests, and must give the correct expected readings/results before the test results can be taken as being accurate.Both positive and negative controls are used.
There is increasing automation in serology. Even in tests that are not automated, the equipment used are designed to save time and space. Microtitre plates replace test tubes. Slides with either Ag or Ab absorbed onto their wells save time in processing.Most procedures use very small amounts of substances/reagents. This saves money as reagents are usually very expensive.
Due to the precise and small amounts of reagents used in serological tests, serology requires the lab worker to be accurate and precise in their work. Amounts are not negotiable. any deviation from this will lead to inaccurate results.
A serial dilution is any dilution where the concentration decreases by the same quantity in each successive step.
double dilutions are a series of ½ dilutions. Each successive tube will ½ the amount of the original concentrated solution.
In any serological test done in the lab, we are looking for an unknown using a known. The known are the reagents that we use, usually commercialy available. The unknown is usually in the patients specimen, and can be either antigen or antibody.
Acute phase serum refers to specimen taken during the disease state, used to diagnose the disease.
Convalescent phase serum is taken after the disease has been treated, and can be used to determine if titre has decreased due to effective treatment.
Serum has no clotting factors present; usually specimen taken in brown top blood collection tube (with no anticoagulants)
Plasma has all clotting factors present; usually collected in purple top tube (containing anticoagulants)
Sterility is not an issue in serology as we are looking for presence of Ag or Ab. Any organisms present will not affect the results
Sensitivity refers to the ability of a serologicl test to identify the Ag or Ab in minute amounts. There will not be any false negative results due to the Ag or Ab being present in very small amounts.
Specificity refers to the ability of a serological test to identify the exact Ag or Ab being tested for. There are no cross reactions giving false positive results.
All serological tests have to be controlled. These controls are put up at the same time as the tests, and must give the correct expected readings/results before the test results can be taken as being accurate.Both positive and negative controls are used.
There is increasing automation in serology. Even in tests that are not automated, the equipment used are designed to save time and space. Microtitre plates replace test tubes. Slides with either Ag or Ab absorbed onto their wells save time in processing.Most procedures use very small amounts of substances/reagents. This saves money as reagents are usually very expensive.
Due to the precise and small amounts of reagents used in serological tests, serology requires the lab worker to be accurate and precise in their work. Amounts are not negotiable. any deviation from this will lead to inaccurate results.
co receptors in cell to cell interactions
We have learnt that TH cells express CD4 which interacts with MHC class II expressed by APC's.
There are other co receptors involved in the above interaction.
TH cell -------------- APC
LFA-2 LFA-3
LFA-1 ICAM-1
CD28 B7
TCR+CD4 MHC class II + peptide
The most important interaction is between CD28 and B7
There are other co receptors involved in the above interaction.
TH cell -------------- APC
LFA-2 LFA-3
LFA-1 ICAM-1
CD28 B7
TCR+CD4 MHC class II + peptide
The most important interaction is between CD28 and B7
HIV infection
2 types: HIV-1 and HIV-2.
HIV-1 is more prevalent and largely responsible for the AIDS pandemic
HIV infection takes place or refers to when a person acquires the HIV virus. The initial illnes (which does not appear in all people) is a ild glandular fever like infection. There is a huge rise in virus levels.
The host's immune response controls the infection and there follows an asymptomatic period. This can last for 8-10 years depending on the host's immune status.The virus continues to multiply during this period.The antigenic makeup of the virus changes as the infection proceeds, which hampers the host's immune response to eradicate the infection.
The HIV virus requires both CD4 and either CXCR5 or CCR5 as co receptors for entry into the host's cells. During the asymptomatic period, the co receptor preference changes from CCR5 to CXCR4.
The level of CD4 cells decreases until AIDS develops. AIDS is characterized by infections with opportunistic organisms.
HIV-1 infections have a shorter asymptomatic period, a quicker progression of disease and higher rates of transmission when compared to HIV-2
Most HIV-1 strains use CCR5 as a co receptor and are known as R5 strains. HIV-1 strains that use CXCR4 as a co receptor are known as X4 strains.
There are some individuals who have had repeated exposure to HIV and not become infected. Their CCR5 genes have mutated. People with homozygous mutations express no CCR5 on their cells and are highly resistant to infection. People with heterozygous mutations have increased resistance to HIV.
HIV-1 is more prevalent and largely responsible for the AIDS pandemic
HIV infection takes place or refers to when a person acquires the HIV virus. The initial illnes (which does not appear in all people) is a ild glandular fever like infection. There is a huge rise in virus levels.
The host's immune response controls the infection and there follows an asymptomatic period. This can last for 8-10 years depending on the host's immune status.The virus continues to multiply during this period.The antigenic makeup of the virus changes as the infection proceeds, which hampers the host's immune response to eradicate the infection.
The HIV virus requires both CD4 and either CXCR5 or CCR5 as co receptors for entry into the host's cells. During the asymptomatic period, the co receptor preference changes from CCR5 to CXCR4.
The level of CD4 cells decreases until AIDS develops. AIDS is characterized by infections with opportunistic organisms.
HIV-1 infections have a shorter asymptomatic period, a quicker progression of disease and higher rates of transmission when compared to HIV-2
Most HIV-1 strains use CCR5 as a co receptor and are known as R5 strains. HIV-1 strains that use CXCR4 as a co receptor are known as X4 strains.
There are some individuals who have had repeated exposure to HIV and not become infected. Their CCR5 genes have mutated. People with homozygous mutations express no CCR5 on their cells and are highly resistant to infection. People with heterozygous mutations have increased resistance to HIV.
Thursday, August 11, 2011
overview after lecture one
Hi guys
So I probably left you reeling after such a long lecture; strange terms and a totally different language. Lots to learn and so much expected of you. I hope that everyone stays the duration of the ride, and if anyone is feeling left out or insecure, that they let me know. I can do something. There is always hope, never fear.
Some things i did not tell you. I expect you to re read all that was covered during lectures. I expect you to have a working knowledge at the following lecture of all that was discussed in the previous lecture. Don't know is not an acceptable answer for any question. At least try an answer, any answer. My door is always open for any student who wants to discuss anything. I am being paid to teach you. Make use of me.
Read read and read. Convert statements to drawings and convert drawings to statements. Teach your neighbour or uncle or dog about what you have learnt. If you can teach someone else, then you really know your stuff. This is also good practice for your project.
Enough for now. Exciting stuff awaits. Are you ready???????
So I probably left you reeling after such a long lecture; strange terms and a totally different language. Lots to learn and so much expected of you. I hope that everyone stays the duration of the ride, and if anyone is feeling left out or insecure, that they let me know. I can do something. There is always hope, never fear.
Some things i did not tell you. I expect you to re read all that was covered during lectures. I expect you to have a working knowledge at the following lecture of all that was discussed in the previous lecture. Don't know is not an acceptable answer for any question. At least try an answer, any answer. My door is always open for any student who wants to discuss anything. I am being paid to teach you. Make use of me.
Read read and read. Convert statements to drawings and convert drawings to statements. Teach your neighbour or uncle or dog about what you have learnt. If you can teach someone else, then you really know your stuff. This is also good practice for your project.
Enough for now. Exciting stuff awaits. Are you ready???????
Thursday, August 4, 2011
Something to think about
If you meet a very anxious mom of a young child at the local clinic and, on asking as what the medical problem of her child is, you get told: "She has a temperature", describe clearly what is wrong in that statement.
Sent via my BlackBerry from Vodacom - let your email find you!
Sent via my BlackBerry from Vodacom - let your email find you!
"This e-mail is subject to our Disclaimer, to view click http://www.dut.ac.za"
immunology project 2011
Hi guys
I thought that I should give you a preview of what you will be expected to do in your immunology project this semester. I had another project in mind but due to the lost lecture time, I have had to make changes.
So I hope that all of you are familiar with youtube and have at least watched one video on the site. I also hope that you have access to a cellphone that has video recording capabilities. So you will video yourself describing a concept or procedure relevant to immunology and upload it to YouTube. I will download the video and after watching it, assess it using a rubric that you will be given shortly. So I guess you have to start sharpening your speaking skills and start doing some research. More details about the project will be provided once I see you. Good luck guys!
"This e-mail is subject to our Disclaimer, to view click http://www.dut.ac.za"
the specific immune response
characteristics of the specific immune response
1. specificity
IR is specific for specific Ag or specific component of Ag; epitopes/determinants = portion of Ag recognized by lymphocytes
2. memory
IS remembers Ag; therefore the second response = quicker, more intense
3. self regulation
feedback regulation of IR; normal IR wanes/decreases after time, return to dormant state
4. diversity
lymphocytes can respond to a very large number of Ag
5. distinguish self from non self i.e. recognizes foreign
IS can distinguish between foreign and self Ag (define self Ag)
The specific immune response has 2 components
1. primary IR
2. secondary IR
primary response
This can be illustrated in a graph showing the different stages as described below
specific Ab appear in blood after 3 – 14 days
latent period (lag phase) involves Ag recognition and development of lymphocyte clones
log phase shows a rise in [Ab] logarithmically until it reaches a peak
IgM is the principal Ab synthesized.
decline phase depicts a drop of [Ab] to very low levels
primary response vs secondary response
(Features of secondary IR that are different to primary IR)
1. more rapid than primary response
2. shorter latent period
3. decreased amount of Ag needed to invoke response
4. more Ab produced
5. decline phase is slower
6. predominant Ab is IgG
7. affinity of Ab increases
remember the above differences as we will be doing an in class exercise using this information.
questions for all students (mainstream and extended group)
Classify the following as either specific, non specific, primary, secondary, non immunogenic:
IV injection of penicillin; Anti diarrhoeal tablets; Inflammation; Sore throat
Fever; Sinusitis; Hay fever; WBC; neutrophils; urine; tears; lysozyme; tea; allergy; no symptoms on exposure to German measles; HIV; AIDS; food; lactose in lactose intolerant people;
1. specificity
IR is specific for specific Ag or specific component of Ag; epitopes/determinants = portion of Ag recognized by lymphocytes
2. memory
IS remembers Ag; therefore the second response = quicker, more intense
3. self regulation
feedback regulation of IR; normal IR wanes/decreases after time, return to dormant state
4. diversity
lymphocytes can respond to a very large number of Ag
5. distinguish self from non self i.e. recognizes foreign
IS can distinguish between foreign and self Ag (define self Ag)
The specific immune response has 2 components
1. primary IR
2. secondary IR
primary response
This can be illustrated in a graph showing the different stages as described below
specific Ab appear in blood after 3 – 14 days
latent period (lag phase) involves Ag recognition and development of lymphocyte clones
log phase shows a rise in [Ab] logarithmically until it reaches a peak
IgM is the principal Ab synthesized.
decline phase depicts a drop of [Ab] to very low levels
primary response vs secondary response
(Features of secondary IR that are different to primary IR)
1. more rapid than primary response
2. shorter latent period
3. decreased amount of Ag needed to invoke response
4. more Ab produced
5. decline phase is slower
6. predominant Ab is IgG
7. affinity of Ab increases
remember the above differences as we will be doing an in class exercise using this information.
questions for all students (mainstream and extended group)
Classify the following as either specific, non specific, primary, secondary, non immunogenic:
IV injection of penicillin; Anti diarrhoeal tablets; Inflammation; Sore throat
Fever; Sinusitis; Hay fever; WBC; neutrophils; urine; tears; lysozyme; tea; allergy; no symptoms on exposure to German measles; HIV; AIDS; food; lactose in lactose intolerant people;
Wednesday, August 3, 2011
lock and key mechanism contd
I can see that a few students are having a problem understanding this concept. Unfortunately I cannot add a picture to this blog. However I have asked you to consult with your matric life science notes. Or you can visit your local library and use their school textbooks or you could search the net. Don't be lazy people, use your initiative
http://www.biologyguide.net/unit1/2_enzymes.htm
http://www.chem4kids.com/files/bio_enzymes.html
try the websites above
http://www.biologyguide.net/unit1/2_enzymes.htm
http://www.chem4kids.com/files/bio_enzymes.html
try the websites above
Tuesday, August 2, 2011
APC's
So how many of you read Victorian novels/romances? Yeah I suppose not many of you are readers, right??? Okay so have any of you watched a like really old movie like Gone with the Wind? where debutantes were presented to society as having learnt all the social graces and are ready for marriage. Obviously all the eligible (rich and handsome helps here) bachelors were invited to these occasions. Rather like a cattle sale, I think..... women for sale (marriage) and men (buyers) on the lookout for the best. Sp how far have we come in South Africa with our interpretation of the debs ball??????
These women were presented and the bill paid by rich relatives, usually old dowager ladies.
So anyway the point I am trying to make here:
APC's (Ag presenting cells) are rather like these old ladies. They present Ag to immune cells (or the immune system) for processing. In most cases ( we will do exceptions later on), Ag will not stimulate an immune response without an APC. Now and APC is not a particular type of cell, but rather a function carried out be specific cells. B cells, monocytes, macrophages, phagocytes, neutrophils, dendritic cells all act as APC's.
These women were presented and the bill paid by rich relatives, usually old dowager ladies.
So anyway the point I am trying to make here:
APC's (Ag presenting cells) are rather like these old ladies. They present Ag to immune cells (or the immune system) for processing. In most cases ( we will do exceptions later on), Ag will not stimulate an immune response without an APC. Now and APC is not a particular type of cell, but rather a function carried out be specific cells. B cells, monocytes, macrophages, phagocytes, neutrophils, dendritic cells all act as APC's.
who are you?
Hi
I have noticed that this blog is being viewed by people other than my intended audience. I have no problem with this. However, I would really appreciate you maybe introducing yourself to me and telling me what benefit you are deriving from this blog. I promise to keep all information confidential. Could you also tell me what field you are involved in?
warm regards
Sherlien
I have noticed that this blog is being viewed by people other than my intended audience. I have no problem with this. However, I would really appreciate you maybe introducing yourself to me and telling me what benefit you are deriving from this blog. I promise to keep all information confidential. Could you also tell me what field you are involved in?
warm regards
Sherlien
Monday, August 1, 2011
classification of specific immune responses
they can be divided into active or passive immunity, and natural or artificial immunity.
in active immunity, energy is expended or used up in creating antibodies. In passive immunity, antibodies are "inherited" or sourced from outside the host's immune system. In a natural immune response, things happen as consequences of day to day living. Artificial immunity refers to us forcing something to take place.
examples:
getting the flu, and recovering is active and natural
immunization is active and artificial
placental transfer is passive and natural
administration of antitoxin is artificial and passive
can you justify the above?
what is the difference between immunization and administration of antitoxin?
what is an antitoxin and in what way does it differ from an antibody?
in active immunity, energy is expended or used up in creating antibodies. In passive immunity, antibodies are "inherited" or sourced from outside the host's immune system. In a natural immune response, things happen as consequences of day to day living. Artificial immunity refers to us forcing something to take place.
examples:
getting the flu, and recovering is active and natural
immunization is active and artificial
placental transfer is passive and natural
administration of antitoxin is artificial and passive
can you justify the above?
what is the difference between immunization and administration of antitoxin?
what is an antitoxin and in what way does it differ from an antibody?
FACTORS INFLUENCING IMMUNOGENICITY CHEMICAL NATURE OF IMMUNOGENS
A. Proteins -The vast majority of immunogens are proteins. These may be pure proteins or they may be glycoproteins or lipoproteins. In general, proteins are usually very good immunogens.
B. Polysaccharides - Pure polysaccharides and lipopolysaccharides are good immunogens.
C. Nucleic Acids - Nucleic acids are usually poorly immunogenic. However, they may become immunogenic when single stranded or when complexed with proteins.
D. Lipids - Lipids are non-immunogenic, although they may be haptens.
question
add these differences to the table you created in the previous post.
Write up the answers/table clearly, with your name and reg no, and bring to class when lectures begin, for assessment.
B. Polysaccharides - Pure polysaccharides and lipopolysaccharides are good immunogens.
C. Nucleic Acids - Nucleic acids are usually poorly immunogenic. However, they may become immunogenic when single stranded or when complexed with proteins.
D. Lipids - Lipids are non-immunogenic, although they may be haptens.
question
add these differences to the table you created in the previous post.
Write up the answers/table clearly, with your name and reg no, and bring to class when lectures begin, for assessment.
FACTORS INFLUENCING IMMUNOGENICITY Contribution of the Immunogen
1. Foreignness - The immune system normally discriminates between self and non-self such that only foreign molecules are immunogenic.
2. Size - There is not absolute size above which a substance will be immunogenic. However, the larger the molecule the more immunogenic it is likely to be.
3. Chemical Composition - The more complex the substance is chemically the more immunogenic it will be. The antigenic determinants are created by the primary sequence of residues in the polymer and/or by the secondary, tertiary or quaternary structure of the molecule.
4. Physical form - Particulate antigens are more immunogenic than soluble ones and denatured antigens more immunogenic than the native form.
5. Degradability - Antigens that are easily phagocytosed are generally more immunogenic. This is because for most antigens (T-dependant antigens) the development of an immune response requires that the antigen be phagocytosed, processed and presented to helper T cells by an antigen.
question
tabulate the differences between immunogenic and non immunogenic for each of the factors described above
2. Size - There is not absolute size above which a substance will be immunogenic. However, the larger the molecule the more immunogenic it is likely to be.
3. Chemical Composition - The more complex the substance is chemically the more immunogenic it will be. The antigenic determinants are created by the primary sequence of residues in the polymer and/or by the secondary, tertiary or quaternary structure of the molecule.
4. Physical form - Particulate antigens are more immunogenic than soluble ones and denatured antigens more immunogenic than the native form.
5. Degradability - Antigens that are easily phagocytosed are generally more immunogenic. This is because for most antigens (T-dependant antigens) the development of an immune response requires that the antigen be phagocytosed, processed and presented to helper T cells by an antigen.
question
tabulate the differences between immunogenic and non immunogenic for each of the factors described above
Thursday, July 28, 2011
cell markers
So how do you recognize another DUT student, even if you dont know him/her? Well these days, its easy cos they are probably looking bored, waiting for lectures to start.
Okay so how do you recognize academic staff of the Biomed dept? I suppose because we look like we belong here, and may have a look of authority about us? I'm not actually sure.
The point i am trying to make is that we use non verbal clues to identify other people.
So how do you suppose cells in the body recognise each other? Do you think they carry signs that say: Hello. I am a Tc cell. Who are you? I think noT!!!!!!!!!!!!!
All cells express (important word used here, remember it) cell markers. A cell marker is a structure found on the surface of a cell. It is not part of the cell membrane, so it cannot be drawn as part of the cell membrane. It is like an address for cells. Different cell markers are found on different cells. Cells 'talk' to each other via cell markers.
Now these cell markers do not actually connect with each other, rather they interact with each other, meaning there is a distinct clear space between each cell marker.
now to the drawing: a spherical shape represents cells. Any shape will represent a cell marker, BUT remember the lock and key mechanism thingy!!!
so i want you to draw me 2 cells interacting with each other via cell markers which 'fit' into each other. NB! no contact between the cell markers. Cell markers are structures on the surface of the cells
now label them as follows:
Tc cell expressing CD8
Th cell expressing CD4
so if we had to write down in words what you just drew:
a Tc cell expressing CD8 interacts with CD4 expressed by Th cell.
makes sense??? if it doesnt, let me know please . Enough for today. Rest now
Okay so how do you recognize academic staff of the Biomed dept? I suppose because we look like we belong here, and may have a look of authority about us? I'm not actually sure.
The point i am trying to make is that we use non verbal clues to identify other people.
So how do you suppose cells in the body recognise each other? Do you think they carry signs that say: Hello. I am a Tc cell. Who are you? I think noT!!!!!!!!!!!!!
All cells express (important word used here, remember it) cell markers. A cell marker is a structure found on the surface of a cell. It is not part of the cell membrane, so it cannot be drawn as part of the cell membrane. It is like an address for cells. Different cell markers are found on different cells. Cells 'talk' to each other via cell markers.
Now these cell markers do not actually connect with each other, rather they interact with each other, meaning there is a distinct clear space between each cell marker.
now to the drawing: a spherical shape represents cells. Any shape will represent a cell marker, BUT remember the lock and key mechanism thingy!!!
so i want you to draw me 2 cells interacting with each other via cell markers which 'fit' into each other. NB! no contact between the cell markers. Cell markers are structures on the surface of the cells
now label them as follows:
Tc cell expressing CD8
Th cell expressing CD4
so if we had to write down in words what you just drew:
a Tc cell expressing CD8 interacts with CD4 expressed by Th cell.
makes sense??? if it doesnt, let me know please . Enough for today. Rest now
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