The response to antigen proceeds at the T helper cell level through two independent forms of cellular collaboration , contact and lymphokine .
the response to antigen proceeds at the t helper cell level through two independent forms of cellular collaboration , contact and lymphokine .
O O O O O O O B-cell_type I-cell_type I-cell_type O O O O O O B-other_name I-other_name O O O B-protein_family_or_group O