Richter M, Talor E
Clin Immunol Immunopathol. 1986 Dec;41(3):461-78. doi: 10.1016/0090-1229(86)90017-6.
Outbred rabbits were immunized intravenously with 10(9) sheep erythrocytes (SRBC) and/or horse erythrocytes (HRBC) and sacrificed 1 to 60 days later. At the height of the immune response (Day 7 postimmunization), antibody-forming cells identified by their ability to form hemolytic plaques in the plaque-forming cell (PFC) assay were detected only in the spleen. The splenic PFCs were totally inhibited if they were first incubated with the autologous thymus cells (immune thymus suppressor cells or ITSCs) for 4 hr prior to assaying for PFCs. Incubation of the spleen mononuclear cells with cells of any of the other lymphoid organs of the immunized rabbit for up to 6 hr did not inhibit the PFCs to any significant degree. There is no MHC restriction in the suppressor activity of the ITSCs since they could totally suppress the PFCs of autologous and allogeneic 7-day immune spleen cells. Neither thymus cells nor cells of any of the other lymphoid organs of the unimmunized rabbit could inhibit allogeneic 7-day immune splenic PFCs. The ITSCs from rabbits immunized with SRBC could be isolated by rosetting with the immunizing antigen, SRBC, but not with the non-cross-reacting antigens HRBC, human erythrocytes (HuRBC), and rabbit erythrocytes (RRBC), and vice versa, thus demonstrating the antigenic specificity of the suppressor cells. The thymus cells, but not the cells of any of the other lymphoid organs of the SRBC-immunized rabbit, secreted a factor referred to as immune thymus suppressor factor (ITSF) during incubation for 4 hr at 37 degrees C which could, by itself, totally suppress the splenic PFC. ITSF could be absorbed out of solution by incubation with the immunizing antigen, SRBC, but not with the non-cross-reacting antigens HRBC, HuRBC, and RRBC. Similarly, the ITSF secreted by the thymus cells of the HRBC-immunized rabbit could be absorbed out of solution by incubation with the immunizing antigen, HRBC, but not with the SRBC, HuRBC, and RRBC. ITSF is therefore antigen specific as is its parent ITSC. The cells of the lymphoid organs of unimmunized rabbits did not secrete a suppressor factor during incubation in vitro. ITSCs capable of totally inhibiting the PFCs were detected in the immunized rabbits by Day 5 post-primary-immunization; the ITSCs were capable of secreting ITSF which could totally inhibit the PFCs by Day 7 post-primary-immunization. Although the ITSCs were detected in a suppressive state up to Day 40 post-primary-immunization, they lost their capacity to secrete ITSF by Day 21 post-primary-immunization.(ABSTRACT TRUNCATED AT 400 WORDS)
将远交群兔静脉注射10⁹个绵羊红细胞（SRBC）和/或马红细胞（HRBC），并在1至60天后处死。在免疫反应高峰期（免疫后第7天），通过在空斑形成细胞（PFC）试验中形成溶血空斑的能力鉴定的抗体形成细胞仅在脾脏中被检测到。如果在检测PFC之前，将脾PFC先与自体胸腺细胞（免疫胸腺抑制细胞或ITSCs）孵育4小时，则脾PFC会被完全抑制。将免疫兔的脾脏单核细胞与任何其他淋巴器官的细胞孵育长达6小时，不会在任何显著程度上抑制PFC。ITSCs的抑制活性不存在MHC限制，因为它们可以完全抑制自体和同种异体7天免疫脾细胞的PFC。未免疫兔的胸腺细胞或任何其他淋巴器官的细胞均不能抑制同种异体7天免疫脾PFC。用SRBC免疫的兔的ITSCs可以通过与免疫抗原SRBC进行花环形成来分离，但不能与非交叉反应抗原HRBC、人红细胞（HuRBC）和兔红细胞（RRBC）分离，反之亦然，从而证明了抑制细胞的抗原特异性。在37℃孵育4小时期间，SRBC免疫兔的胸腺细胞而非任何其他淋巴器官的细胞分泌一种称为免疫胸腺抑制因子（ITSF）的因子，其本身可以完全抑制脾PFC。通过与免疫抗原SRBC孵育，ITSF可以从溶液中被吸收，但不能与非交叉反应抗原HRBC、HuRBC和RRBC吸收。同样，通过与免疫抗原HRBC孵育，HRBC免疫兔的胸腺细胞分泌的ITSF可以从溶液中被吸收，但不能与SRBC、HuRBC和RRBC吸收。因此，ITSF与其母体ITSC一样具有抗原特异性。未免疫兔的淋巴器官细胞在体外孵育期间不分泌抑制因子。在初次免疫后第5天在免疫兔中检测到能够完全抑制PFC的ITSCs；到初次免疫后第7天，ITSCs能够分泌ITSF，其可以完全抑制PFC。尽管在初次免疫后第40天之前ITSCs一直处于抑制状态，但到初次免疫后第21天它们失去了分泌ITSF的能力。（摘要截断于400字）
