CD4 and tuberculosis: While B cells are known to modulate T cell responses, their role during helminth/TB co-infection remains unclear.<h4>Objective</h4>This study aimed to analyze the effect of helminth exposure on T cell activation in a T and B cell co-culture system.<h4>Methods</h4>T and B cells were isolated from healthy donor blood, stimulated with aCD3/aCD28, and exposed to <i>Ascaris lumbricoides</i> protein antigens (ASC) or <i>Schistosoma mansoni</i> soluble egg antigen (SM).<h4>Results</h4>B cells reduced T cell proliferation, and SM exposure partly attenuated this inhibitory effect on CD4 T cells.