Abstract
A specific suppression of the splenic anti‐NIP (4‐hydroxy‐5‐iodo‐3‐nitropheyl)acetyl plaque‐forming cell response to NIP. FGG (fowl IgG) was obtained in CBA/J mice by pretreatment with NIP‐coated syngeneic erythrocytes. If the plaque assay was carried out at 7 days after challenge with NIP. FGG, a complete suppression of the indirect anti‐NIP plaque‐forming cell (PFC) response could be obtained, but there was no significant decrease in the direct anti‐NIP PFC response at this stage. Complete suppression of the day 7 indirect PFC response occurred within 5–7 days after the NIP‐coated erythrocyte treatment, and lasted for 1–2 months. The degree of suppression was found to depend on the dose of the erythrocytes and on the amount of NIP coupled to them. On closer examination of the anti‐NIP PFC response at different time intervals after the NIP. FGG challenge, it became apparent that there was a slight increase in the indirect anti‐NIP PFC response at days later than day 7. A definite suppression of the direct anti‐NIP PFC cell response was observed earlier than at day 7.
The state of hapten‐specific suppression could be reversed by the addition of syngeneic spleen cells at the time of antigen challenge. The suppression was found to extend to the serum anti‐NIP antibody levels and could also be induced in animals previously primed with NIP‐FGG.