Justify the statement below

Question

1. T dependent antigens are more useful in generation of the immune response

.2 Costimulatory signal is under regulation by the membrane molecules

.3 Small fragments generated during complement activation are important.

4.All antigens are immunogens

5.All Ig molecules on the surface of a given B cell have the same idiotype.

6.Superantigens can induce polyclonal lymphocyte proliferation

7Enzyme digested Antibody molecules can still form a complex lattice with respect to

Specific antigen.

8.Antibody can share the same ag binding site to different types of antibodies

Answer 1

1. This is true becuase T-cell-dependent responses give you class switch to the more useful, more tissue-infiltrating IgG class, and they also give you memory and somatic hypermutation.
2. Yes. The majorly important one is B7 on pAPCs, which binds to CD28 on T cells.
3. This is true because the a components serve as inflammatory mediators, chemoattractants, and also increase microbicidal capacity of phagocytes like macrophages. They also activate mast cells to promote release of inflammatory compounds like histamine.
4. This isn't necessarily true, as an immune response isn't activated against every antigen. For example, self antigens will not elicit an immune response. However, if you find a host to which the antigen is foreign, I suppose you could say any antigen can be an immunogen.
5. This is just fact. The only exception is immature and mature naive B cells, who have both IgM and IgD.
6. They do so by binding TCR:MHCII complexes and holding them together, which tricks the T cell into thinking it's been activated.
7. Take papain for an example. The antigen-binding fragment still remains intact and can still bind specific antigen.
8. This is true because class switch only affects the constant region--not the antigen-binding region.