Strickland G T, Ahmed A, Sell K W
Clin Exp Immunol. 1975 Oct;22(1):167-76.
In order to differentially test the function of lymphocytes in Toxoplasma gondii-infected mice, the in vitro blastogenic response of spleen cell cultures to non-specific mitogens was studied. Phytohaemagglutinin (PHA) and concanavalin A (Con A) stimulation were used as tests of thymus-dependent lymphocyte (T cell) function and bacterial endotoxin lipopolysaccharide (LPS) was used as a probe of bursal equivalent lymphocyte (B cell) function. For the first 3 weeks following T. gondii infection, the uptake of tritiated thymidine ([3H]TdR) by spleen cells cultured with all three mitogens was markedly reduced in comparison to the uptake in spleen cells from uninfected control mice. Thereafter, the response to LPS returned to normal while stimulation by the T-cell mitogens (PHA and Con A) remained depressed. It is postulated that T. gondii infection either: (1) diluted out T cells in the spleen with unreactive cells; (2) modified T cells in such a way that they were less responsive to mitogens; (3) depleted the peripheral lymphoid tissues of T cells; (4) induced non-specific suppressor cells, which inhibited the T-cell function assays; or (5) activated macrophages which depressed T-cell function non-specifically.
为了鉴别检测弓形虫感染小鼠中淋巴细胞的功能，研究了脾细胞培养物对非特异性有丝分裂原的体外增殖反应。使用植物血凝素（PHA）和刀豆球蛋白A（Con A）刺激来检测胸腺依赖性淋巴细胞（T细胞）功能，使用细菌内毒素脂多糖（LPS）作为法氏囊等同淋巴细胞（B细胞）功能的探针。在弓形虫感染后的前3周，与未感染对照小鼠的脾细胞摄取相比，用所有三种有丝分裂原培养的脾细胞对氚标记胸腺嘧啶核苷（[3H]TdR）的摄取明显减少。此后，对LPS的反应恢复正常，而T细胞有丝分裂原（PHA和Con A）的刺激仍受到抑制。据推测，弓形虫感染要么：（1）用无反应性细胞稀释脾脏中的T细胞；（2）以使其对有丝分裂原反应性降低的方式修饰T细胞；（3）耗尽外周淋巴组织中的T细胞；（4）诱导非特异性抑制细胞，其抑制T细胞功能检测；要么（5）激活巨噬细胞，非特异性地抑制T细胞功能。
