Bankert R B, Pressman D
J Immunol. 1976 Aug;117(2):457-62.
Previous studies have shown that rabbit antibody-forming cells in the primary and secondary response possess cell-associated antigen-binding receptors. In the present study, we demonstrate that a factor appears in the serum of rabbits following immunization which inhibits the antigen binding of up to 60% of the receptor-bearing antibody-forming cells in both the primary and secondary response. These observations were made on lymph node cells from rabbits primed with either sheep red blood cells (SRBC)3 or 3-nitro-4-hydroxy-5-iodophenylacetic acid coupled to keyhole limpet hemocyanin (NIP-KLH). The inhibitory activity is not associated with anti-SRBC or anti-NIP antibody. In the primary response to SRBC, the antigen binding by day 6 antibody-forming cells is inhibited by the autologous days 7 to 10 inactivated and absorbed serum. In the secondary response to SRBC, the inhibitory factor peaks in the serum around day 10. Later, in both the primary and secondary immune response to SRBC, the inhibitory activity of the serum decreases rapidly. In the primary response to NIP-KLH, the inhibitory activity of the immune sera increased from day 7 through day 14. The receptor-inhibiting factor is antigen specific since the serum from SRBC-primed rabbits inhibits SRBC binding by anti-SRBC antibody-forming cells, but it does not inhibit NIP binding by anti-NIP antibody-forming cells. Similarly, serum from NIP-KLH-primed rabbits inhibits NIP binding by anti-NIP antibody-forming cells, but does not inhibit the SRBC receptor on the anti-SRBC antibody-forming cells. The inhibition is not due to the presence of antihapten or anti-SRBC antibody competing with receptor sites, since the immune sera from one SRBC-primed animal inhibit antigen binding of its own antibody-forming cells, but do not inhibit the antigen binding of antibody-forming cells from other SRBC-primed rabbits.
先前的研究表明，家兔在初次和再次免疫应答中的抗体形成细胞拥有与细胞相关的抗原结合受体。在本研究中，我们证明，家兔免疫后血清中会出现一种因子，该因子在初次和再次免疫应答中可抑制高达60%的带有受体的抗体形成细胞的抗原结合。这些观察结果是在用绵羊红细胞（SRBC）3或与钥孔戚血蓝蛋白偶联的3-硝基-4-羟基-5-碘苯乙酸（NIP-KLH）致敏的家兔的淋巴结细胞上进行的。抑制活性与抗SRBC或抗NIP抗体无关。在对SRBC的初次免疫应答中，第6天抗体形成细胞的抗原结合受到第7至10天自身灭活并吸收的血清的抑制。在对SRBC的再次免疫应答中，抑制因子在第10天左右在血清中达到峰值。随后，在对SRBC的初次和再次免疫应答中，血清的抑制活性迅速下降。在对NIP-KLH的初次免疫应答中，免疫血清的抑制活性从第7天到第14天增加。受体抑制因子具有抗原特异性，因为用SRBC致敏的家兔的血清可抑制抗SRBC抗体形成细胞与SRBC的结合，但不抑制抗NIP抗体形成细胞与NIP的结合。同样，用NIP-KLH致敏的家兔的血清可抑制抗NIP抗体形成细胞与NIP的结合，但不抑制抗SRBC抗体形成细胞上的SRBC受体。这种抑制不是由于存在与受体位点竞争的抗半抗原或抗SRBC抗体，因为来自一只用SRBC致敏的动物的免疫血清可抑制其自身抗体形成细胞的抗原结合，但不抑制来自其他用SRBC致敏的家兔的抗体形成细胞的抗原结合。
