Antigens that lack a peptide component & cannot be presented on MHC to T-cells
Thymus-independent antigens
Weakly immunogenic antigens
Thymus-independent antigens like lipopolysaccharides from gram-negative bacteria
Vaccines that are weakly immunogenic often require…
boosters and adjuvants like pneumococcal polysaccharide vaccine
Antigens containing a protein component
Thymus-dependent antigens
Strong immunogenic antigens
Thymus-dependent antigens like diphtheria vaccine
Promote class switching and immunologic memory by direct contact of B-cells with Th cells
Thymus-dependent antigens