Analysis of pathogenesis of primary infection and reactivation of HHV-6

1) exanthem subitum患者对HHV-6的淋巴细胞增殖反应：细胞增殖ELISA （Boehringer）评估原发性HHV-6感染后淋巴细胞增殖反应（刺激指数（si））动力学如下；急性期：1.2，感染后1周：1.3，感染后1个月：1.9。所有si均低于健康成人（si =5）。1) 2)原发性HHV-6感染后的免疫抑制：为了评估每个患者的免疫状况，对所有样本进行PHA刺激淋巴细胞增殖反应的检测。在病毒感染后1个月内，淋巴细胞增生反应明显减弱。这一结果表明，非特异性免疫反应可能在原发性HHV-6感染后1个月内受损。3)病毒抗原的纯化为了提高原抗原的非特异性刺激，采用密度梯度法纯化抗原。虽然纯化后的抗原在大多数样品中显示出较低的背景值，但部分样品仍显示出较高的背景值。据推测，用于制备抗原的脐带血单核细胞HLA可能是导致该问题的原因。4) HHV-6感染K562细胞：由于K562细胞表面不表达HLA I类抗原，我们尝试将HHV-6感染到细胞中。然而，病毒感染细胞的效率很低。

1) Lymphoproliferative response against HHV-6 in patients with exanthem subitum : Kinetics of the lymphoproliferative response (stimulation index (S.I.)), which was evaluated by Cell Proliferation ELISA (Boehringer), after primary HHV-6 infection is as follows ; acute phase : 1.2, 1 week after infection : 1.3, 1month after infection : 1.9. All S.I. Were lower than that in healthy adults (S.I.=5. 1).2) Immunosuppression after primary HHV-6 infection : In order to evaluate immunological status hi each patient, lymphoproliferative response by PHA stimulation was tested hi all samples. Lymphoproliferative response by the stimulation decreased clearly during first 1 -month period after the virus infection. This result suggests that non-specific immune response could be impaired during 1 month after primary HHV-6 infection.3) Purification of the virus antigeif In order to improve non-specific stimulation by the crude antigen, the antigen was purified by density gradient method. Although the purified antigen demonstrated lower background value in most samples, some samples still showed high background value. It is speculated that HLA type of cord blood mononuclear cells that is used for preparation of the antigen, could cause the problem.4) HHV-6 infection hi K562 cells : Since K562 cells dose not express HLA class I antigen on the surfaces, we attempted to infect HHV-6 into the cells. However, efficiency of the virus infection hi the cells was very low.