Gallego S, Recalde A, Gastaldello R, Isa M, Nates S, Medeot S
Institute of Virology Dr. J.M. Vanella, School of Medical Sciences, National University of Córdoba, Argentina.
Viral Immunol. 1997;10(3):149-57. doi: 10.1089/vim.1997.10.149.
Indirect immunofluorescence assay (IFA) is a well-accepted assay for the confirmation of human retrovirus infection. Fluctuations in HIV-1 antigen expression in infected E-B2 cells depending on several factors have been reported. Cells kept in log phase expressed the highest levels of viral antigen. Thus, we studied the time kinetics of IFA positivity in MT-2 (HTLV-I), MO-T (HTLV-II), CEM, and H9 (HIV-1) cell lines. Uninfected T cell line, HT, was used as nonspecific control. Reference HTLV-I/II and HIV-1 serum panels from the Centers for Disease Control and Prevention (CDC) were tested by conventional IFA procedure on slides of each cell line made on different days. On the second day after subculture, HTLV-I strongly positive sera reacted on MT-2 and MO-T cells with a bright pericytoplasmic fluorescence pattern. Weakly positive sera showed a faint staining from the fifth day on, when all the sera showed the highest degree of fluorescence. With HIV-1 cell lines, sera predominantly reacted with a diffuse cytoplasmic pattern, although some sera showed a granular and pericytoplasmic capping staining. The highest degree of fluorescence was found at 3-5 days after subculture. We demonstrated that the sensitivity of the IFA for the detection of antibodies against human retroviruses depended on the day when the slides were assayed and on the serum antibody titer. The fifth day was the most appropriate for HTLV-I/II and HIV-1/H9 systems, whereas for HIV-1/CEM, the fourth day was better. Furthermore, the intensity of the immunofluorescence pattern differed with the antibody titers and the level of antigens expressed on the four cell lines studied. The IFA, improved in our laboratory, proved to be very sensitive, specific, and rapid and could be used as a supplementary/confirmatory assay for retrovirus infection.
间接免疫荧光测定法（IFA）是一种广泛认可的用于确认人类逆转录病毒感染的测定方法。据报道，受感染的E - B2细胞中HIV - 1抗原表达会因多种因素而波动。处于对数期的细胞表达的病毒抗原水平最高。因此，我们研究了MT - 2（HTLV - I）、MO - T（HTLV - II）、CEM和H9（HIV - 1）细胞系中IFA阳性的时间动力学。未感染的T细胞系HT用作非特异性对照。来自疾病控制与预防中心（CDC）的参考HTLV - I/II和HIV - 1血清板，通过常规IFA程序在不同日期制备的每个细胞系的载玻片上进行检测。在传代培养后的第二天，HTLV - I强阳性血清在MT - 2和MO - T细胞上产生明亮的胞质周围荧光模式反应。弱阳性血清从第五天开始显示微弱染色，此时所有血清显示出最高程度的荧光。对于HIV - 1细胞系，血清主要以弥漫性胞质模式反应，尽管一些血清显示出颗粒状和胞质周围帽状染色。在传代培养后3 - 5天发现荧光程度最高。我们证明，IFA检测抗人类逆转录病毒抗体的敏感性取决于检测载玻片的日期和血清抗体滴度。第五天对于HTLV - I/II和HIV - 1/H9系统最合适，而对于HIV - 1/CEM，第四天更好。此外，免疫荧光模式的强度因抗体滴度和在所研究的四种细胞系上表达的抗原水平而异。我们实验室改进后的IFA被证明非常灵敏、特异且快速，可作为逆转录病毒感染的补充/确证测定方法。
