TH1-cell dependent response
The bulk of the pathogen-specific antibodies come from B-cells stimulated by thymus-dependent (TD) antigens. Activation of these B cells occurs in the secondary lymphoid tissue where B cells, specific antigen and CD4-T helper cells are brought together. CD4-T cells can differentiate along two pathways giving rise to either CD4 TH1 or TH2 cells. The cytokines produced by effector TH1 or TH2 cells also tend to suppress each other, pointing the response in one direction.
TH1 cells give the most effective response to microorganisms. They secrete cytokines that activate macrophages, which then destroy the bacteria they contain. They also activate B cells to produce opsonizing antibodies such as IgG-1.
(Text taken from “the immune system”, Parham, Garland Publishing 2000 page 142,143.)
T-helper cells are the most effective response to micro-organisms because they:
Extra info: Because the macrophages are directed to immediately destroy the offending agent, this brings about the most rapid and complete response.
Infection with Mycobacterium tuberculosis evokes which of the following cytokine profiles?
Extra info: M. tuberculosis infection evokes the early synthesis of IL-12 by cells of the innate immune system which drives the differentiation of CD4+ TH0 cells to TH1 cells which synthesize IL-2, IFN-g, and TNF-a.