Question

Why do commensal bacteria not lead to a strong immune response?

1) Some commensal bacteria lack virulence factors
2) Some commensal bacteria are kept in check by IgA and antimicrobial peptides
3) Some commensal bacteria lack some PAMPs
4) Some commensal bacteria's antigens are presented to T cells by immature dendritic cells
5) all of the above

Answer 1

Commensal bacteria coexist with the host without causing a strong immune response due to the absence of virulence factors, regulation by IgA and antimicrobial peptides, lacking certain PAMPs, and immature dendritic cells promoting tolerance.

Step-by-step explanation:

Commensal bacteria do not generally lead to a strong immune response for several reasons:

• Commensal bacteria often lack virulence factors that are necessary for causing disease.
• Mechanisms such as IgA and antimicrobial peptides help keep these bacteria in check.
• Some commensal bacteria may be missing pathogen-associated molecular patterns (PAMPs) that are typically recognized by the immune system.
• When antigens from commensal bacteria are presented to T cells by immature dendritic cells, it can lead to tolerance rather than an active immune response.

Together, these factors contribute to a situation where commensal bacteria can coexist with the host without triggering a full-blown immune response.