Characterization of responding cells in oxidative mitogen stimulation. I. Ia ⁺ cells and Ly-1 ⁺2 ⁺ cells are required for the proliferative response

Addition of anti-Ia sera to cultures of mouse spleen cells stimulated with oxidative mitogens, neuraminidase/galactose oxidase (NaGO) or sodium periodate (NaIO ₄), inhibits the subsequent proliferative response 30 to 70%. Anti-H-2K or D sera were not specifically inhibitory. Similar inhibition was seen when cells were pretreated with anti-Ia sera and washed before exposure to the mitogenic enzymes. Treatment with anti-Ia serum and complement depletes greater than 89% of the NaGO and the NaIO ₄ responses but 2% or less of the phytohemagglutinin (PHA) response. The response to NaGO was sensitive to depletion with anti-Thy-1 serum, rabbit antimouse brain serum, anti-Ly-1, or anti-Ly-2 serum. Mixtures of Ly-1 and Ly-2-depleted populations did not restore responsiveness. Thus both an Ia ⁺ cell and an Ly-1 ⁺2 ⁺ T cell are required for [ ³H]TdR incorporation in response to NaGO treatment.