Question

How are B cells activated without the help of T cells?

a. this cannot happen
b. repetitive epitopes allow B cell receptor cross-linking, which leads to cell activation and proliferation
c. B cells get help from the complement system
d. B cells get help from macrophages instead

Answer 1

B cells can be activated without the help of T cells through repetitive epitopes present in T-independent antigens. This cross-linkage of B cell receptors leads to activation and proliferation. The second signal for activation can come from interactions with toll-like receptors or factors from the complement system.

Step-by-step explanation:

T cell-independent activation of B cells can occur through repetitive epitopes present in T-independent antigens. These repetitive epitopes allow for the cross-linkage of multiple B cell receptors (BCRs), which provides the first signal for B cell activation and proliferation. The second signal for activation can come from interactions between toll-like receptors (TLRs) and pathogen-associated molecular patterns (PAMPs) or from factors from the complement system.