Cafruny W A, Plagemann P G
Infect Immun. 1982 Sep;37(3):1007-12. doi: 10.1128/iai.37.3.1007-1012.1982.
A rabbit was immunized with large amounts of the lactate dehydrogenase-elevating virus (LDV) over a 9-month period. The plasma from this rabbit possessed an anti-LDV IgG titer of 1:80,000 as measured by the enzyme-linked immunosorbent assay (ELISA) method and a neutralizing titer of 1:1,000 for the homologous strain of LDV. LDV neutralization at 4 degrees C followed single-hit kinetics. In contrast, mouse anti-LDV IgG in plasma of chronically LDV-infected mice failed to neutralize LDV at 4 degrees C and neutralization at 37 degrees C was slow, biphasic, and inefficient compared with the neutralization caused by rabbit anti-LDV IgG, even though high levels of anti-LDV IgG were detectable in mouse plasma by the ELISA method. Rabbit anti-LDV IgG neutralized one heterologous strain of LDV as rapidly as it did the homologous strain, but failed to significantly neutralize five other strains of LDV, all of which were originally isolated from different mouse strains bearing transplantable tumors. The results indicate clear serological differences between LDV strains. Cross-reactions between the strains, however, were observed by ELISA, using the antibody induced during persistent infection of mice with each LDV strain. Immunoglobulin M (IgM) from mice infected for 15 days with the various strains bound equally to our LDV strain. IgG obtained from 2-month-infected mice also cross-reacted, but to a varying extent which partly correlated with the specificity detected by neutralization. Both rabbit and mouse anti-LDV IgG enhanced the infectivity of LDV at a low multiplicity of infection for primary cultures of peritoneal mouse macrophages.
在9个月的时间里，用大量乳酸脱氢酶升高病毒（LDV）免疫一只兔子。通过酶联免疫吸附测定（ELISA）法测得，这只兔子的血浆中抗LDV IgG滴度为1:80,000，对同源LDV株的中和滴度为1:1,000。4℃下的LDV中和遵循单 hit 动力学。相比之下，慢性感染LDV的小鼠血浆中的小鼠抗LDV IgG在4℃下不能中和LDV，并且与兔抗LDV IgG引起的中和相比，37℃下的中和缓慢、呈双相且效率低下，尽管通过ELISA法在小鼠血浆中可检测到高水平的抗LDV IgG。兔抗LDV IgG中和一种异源LDV株的速度与中和同源株一样快，但未能显著中和其他五种LDV株，所有这些株最初均从携带可移植肿瘤的不同小鼠株中分离得到。结果表明LDV株之间存在明显的血清学差异。然而，使用每种LDV株持续感染小鼠期间诱导产生的抗体，通过ELISA观察到了各株之间的交叉反应。感染各种毒株15天的小鼠的免疫球蛋白M（IgM）与我们的LDV株的结合程度相同。从感染2个月的小鼠获得的IgG也发生了交叉反应，但程度不同，这部分与中和检测到的特异性相关。在低感染复数下，兔和小鼠抗LDV IgG均增强了LDV对小鼠腹膜巨噬细胞原代培养物的感染性。
