Requirement for Cellular Interaction in the Antibody Response to Bacteriophage T₄ in Mice¹

Pooled spleen cell suspensions were obtained from CBA mice immunized with 5 × 10⁸ plaque-forming units (PFU) T₄ bacteriophage at times up to 7 days previously, and were transferred into normal isogenic recipients. Analysis of the sera of recipient mice showed that little or no antibody was produced unless the transferred cells were isolated at times when the donors were already making high levels of anti-T₄ antibody. It is considered that, for this antigen at least, there is a critical period during the early part of the response when the integrity of the spleen is essential, and when cell-to-cell interactions may occur.