The preferential effects of chloroquine on the IgM and IgG subclass responses to TI and TD antigens in BALB/cAn mice

Abstract

This study has determined the effects of chloroquine on the IgM and the IgG subclass responses of BALB/cAn mice to both thymus-independent (TI) and thymus-dependent (TD) antigens, and has found that in antigen-unprimed BALB/cAn mice chloroquine adversely affects antibody responses to both TI and TD antigens. However, in antigen-primed mice the immune responses to TD antigens were unaffected by chloroquine. The IgGl subclass response, but not necessarily other IgG subclass or IgM responses to TI and TD antigens, was adversely affected by chloroquine in unprimed mice only. Thus, in unprimed, but not in antigen-primed, BALB/cAn mice, chloroquine preferentially decreased the IgGl subclass responses to both TI and TD antigens.

Malaria: drug use and the immune response

“…A surprising result that might explain variations in response to vaccines was obtained when the effect of chloroquine on the immune responses to thymusdependent and T-independent antigens was assessed in mice. There was no measurable effect on IgM or IgG responses in antigen-primed mice but, in unprimed animals, IgGl responses to both Tdependent and T-independent antigens were depressed by chloroquine (Lewis & Slack, 1990). The reason may again be a consequence of the lyzosomotropic property of this drug affecting antigenprocessing in a specific manner.…”