Yu S, Nakafusa Y, Flye M W
Department of Surgery, Washington University School of Medicine, St. Louis, MO.
Surgery. 1994 Aug;116(2):229-34; discussion 234-5.
Major histocompatibility complex-mismatched Lewis rate cardiac grafts (inferior vena cava drained) are promptly rejected by Buffalo recipients (mean survival time, 7 days). Ultraviolet-B (UVB) irradiation modulates donor immunogenicity and down-regulates in vitro immune responses. We found that Buffalo recipients (BUF; RT1b) preimmunized with 2.5 x 10(7) nontreated Lewis spleen cells (LEW; RT1(1)) by portal venous (PV) injection 7 days before a portal vein-drained heterotopic graft of LEW heart resulted in only 20% surviving long-term (n = 10) (naive rats rejected a cardiac allograft drained into the portal vein in mean survival time of 13.5 days [n = 5]). In contrast, BUF recipients receiving PV injection of UVB-treated LEW spleen cells permitted 70.6% indefinite allograft survival (n = 34) with a mean survival time of greater than 150 days.
These studies examined the effect of untreated or UVB-irradiated donor spleen cells administered intraportally on the recipient's cell-mediated responsiveness as serially measured by the mixed lymphocyte culture and limiting dilution analysis of T-helper precursors (pTH) and cytotoxic precursors (pCTL). Survival of heterotopic cardiac allografts transplanted with PV drainage at various intervals after PV alloantigen administration were correlated with changes in these in vitro studies.
The precursor frequencies in the spleens of BUF recipients given nontreated LEW spleen cells intraportally 7 days previously were 1/16,170 (pTH) and 1/11,929 (pCTL), whereas those in the spleen of BUF recipients receiving UVB-treated LEW spleen cells decreased to 1/152,409 pTH and < 1/5 X 10(5) pCTL. These hyporesponsive BUF spleen cells responded normally to the third-party alloantigen, irradiated ACI spleen cells (RT1 alpha), with mixed lymphocyte culture tritiated incorporation of 133,220 cpm (control, 123,276 cpm), 1/13,364 pTH (control, 1/13,541), and 1/71,156 pCTL (control, 1/73,985), indicating that the hyporesponsiveness induced by UVB-treated donor spleen cells is antigen specific. The recovery of in vitro responsiveness correlates with decreasing cardiac graft survival to normal rejection times by 200 days after portal vein antigen administration. When 100 units/ml exogenous recombinant interleukin-2 (rIL-2), but not rIL-1 or rIL-4, was added to cultures, the hyporesponsiveness of spleen cells recovered to normal levels with tritiated incorporation of 201,227 cpm and pTH frequency of 1/32,227, suggesting that the hyporesponsiveness to donor antigen is due to anergized T-helper lymphocytes and not to clonal deletion.
By administering properly modified alloantigen into the hepatic environment by portal vein inoculation, prolonged T-cell anergy can be induced, which allows the indefinite acceptance of donor-specific heterotopic cardiac allografts.
主要组织相容性复合体不匹配的Lewis大鼠心脏移植物（经下腔静脉引流）会被布法罗大鼠受体迅速排斥（平均存活时间为7天）。紫外线B（UVB）照射可调节供体免疫原性并下调体外免疫反应。我们发现，在门静脉引流的Lewis心脏异位移植前7天，通过门静脉（PV）注射2.5×10⁷个未处理的Lewis脾细胞（LEW；RT1¹）对布法罗大鼠受体（BUF；RT1b）进行预免疫，结果只有20%的受体长期存活（n = 10）（未免疫的大鼠排斥经门静脉引流的心脏同种异体移植物的平均存活时间为13.5天[n = 5]）。相比之下，接受PV注射UVB处理的LEW脾细胞的BUF受体中，70.6%的受体实现了同种异体移植物的无限期存活（n = 34），平均存活时间超过150天。
这些研究通过混合淋巴细胞培养以及对T辅助前体细胞（pTH）和细胞毒性前体细胞（pCTL）的有限稀释分析，连续检测门静脉内注射未处理或UVB照射的供体脾细胞对受体细胞介导反应性的影响。在给予PV同种异体抗原后的不同时间间隔进行PV引流的异位心脏同种异体移植的存活情况，与这些体外研究中的变化相关联。
7天前经门静脉给予未处理的LEW脾细胞的BUF受体脾脏中的前体细胞频率分别为1/16,170（pTH）和1/11,929（pCTL），而接受UVB处理的LEW脾细胞的BUF受体脾脏中的前体细胞频率降至1/152,409 pTH和<1/5×10⁵ pCTL。这些低反应性的BUF脾细胞对第三方同种异体抗原（经照射的ACI脾细胞（RT1α））反应正常，混合淋巴细胞培养中氚掺入量为133,220 cpm（对照组为123,276 cpm），pTH频率为1/13,364（对照组为1/13,541），pCTL频率为1/71,156（对照组为1/73,985），这表明UVB处理的供体脾细胞诱导的低反应性是抗原特异性的。体外反应性的恢复与门静脉抗原给药后200天内心脏移植物存活时间缩短至正常排斥时间相关。当向培养物中添加100单位/ml的外源性重组白细胞介素-2（rIL-2）而非rIL-1或rIL-4时，脾细胞的低反应性恢复到正常水平，氚掺入量为201,227 cpm，pTH频率为1/32,227，这表明对供体抗原的低反应性是由于T辅助淋巴细胞失能而非克隆清除。
通过门静脉接种将经过适当修饰的同种异体抗原引入肝脏环境，可诱导T细胞长期失能，从而使受体能够无限期接受供体特异性的异位心脏同种异体移植物。
