Cm. Snapper et al., Distinct types of T-cell help for the induction of a humoral immune response to Streptococcus pneumoniae, TRENDS IMMU, 22(6), 2001, pp. 308-311
Studies have indicated that purified soluble polysaccharide antigens can el
icit T cell-independent Ig responses in vivo, although these responses can
be modulated by T cells in a noncognate manner. Relatively little is known,
however, concerning the parameters that regulate polysaccharide-specific.
as well as protein-specific, Ig isotype responses to an intact extracellula
r bacterium. Using the murine in vivo humoral response to intact Streptococ
cus pneumoniae as a model it can be shown that CD4(+) T-cell receptor alpha
beta (+) T cells deliver help for both polysaccharide- and protein-specifi
c Ig responses. However, these responses differ fundamentally in their mech
anism of action.