We investigated the photoinactivation of virus infectivity by hypocrellin A and its mechanism. The titers of vesicular stomatitis virus (VSV) and human immunodeficiency virus type 1 (HIV-1), both of which are enveloped viruses, were reduced upon illumination with hypocrellin A in a concentration-dependent manner, whereas canine parvovirus, a nonenveloped virus, was not killed. The removal of oxygen or addition of sodium azide or beta-carotene both inhibited VSV inactivation. Mannitol and superoxide dismutase had no effect on VSV inactivation. These results indicate that singlet oxygen was involved in the process of VSV inactivation. Of the three major VSV membrane proteins, peripheral membrane protein M was most damaged by the hypocrellin A phototreatment.

A human-mouse heterohybridoma (HMR0921) secreting human monoclonal IgG3, lambda antibody was produced from peripheral blood lymphocytes of a healthy blood donor with serum antibody to Jra, by EBV transformation and hybridization with mouse myeloma cell line P3X63Ag8.653. The reactivity of HMR0921 antibody was assessed by antiglobulin test with a panel of red cells including 14 different rare blood types. Only Jr(a-) red cells were negative. The strict specificity of this antibody to Jra antigen was further confirmed by absorption test with fluorescence flow cytometry. On screening of 28,744 blood donor samples by HMR0921 antibody, we detected 19 agglutination-negative samples, which were confirmed as Jr(a-) by conventional anti-Jra antisera. Therefore, our HMR0921 antibody is extremely useful for detecting rare Jr(a-) blood.

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The PCR method was introduced to detect cytomegalovirus (CMV) DNA from 189 peripheral blood samples of volunteer donors. We adopted the nested double PCR method with primers specific for immediate early gene 1 followed by electrophoresis and ethidium bromide staining. This nested double PCR method was sensitive enough to detect approximately a single copy of CMV DNA. However, we failed to obtain positive amplification of CMV DNA from any of these donor samples. In contrast, CMV DNA could be detected in all 3 tested immunocompromised patients who had undergone bone marrow transplantation. These results support our previous report that the frequency of CMV DNA is of an order lower than 1 copy/10(5) leucocytes in the peripheral blood of healthy seropositive individuals.

Spontaneous production of interferon-gamma (IFN-gamma) was shown in several T-lymphoblastoid cell lines persistently infected with human T-lymphotropic virus (HTLV-1). However, the produced IFN-gamma was not always associated with the induction of the antivirus state. The induction of oligo-2',5'-adenylate synthetase (2-5AS) by IFN was studied in five human T-cell lines persistently infected with HTLV-I (MT-1, MT-2, SMT-1, HUT 102 and OKM-2). Four cell lines are able to produce IFN-gamma spontaneously, while the OKM-2 cell line is not. Poor induction of 2-5AS was recognized in three (MT-1, MT-2 and SMT-1) of the four cell lines producing IFN-gamma, though the poor induction was improved after long-term cultivation of cells with IFN-alpha. On the contrary, in the OKM-2 cell line, significant activity of the enzyme was induced by IFN-alpha. Induction of 2-5AS was not correlated with cell growth inhibition, but with the antivirus state. Furthermore, an inverse relationship between IFN-gamma production and 2-5AS induction was demonstrated in these cell lines with the exception of HUT 102 cells.