Delsworth G. Harnish

Repeatability of interview-derived information on sexual history: a study in women.

We assessed the repeatability of interview-derived information on age at first sexual intercourse and number of sexual partners in women participating in an ongoing prospective study of genital human papillomavirus infection in Toronto, Canada. Of the 100 study participants invited to attend for re-interview twice during their first year in the study, 74 attended for the first follow-up interview about 5 months after recruitment, and 28 of these 74 subjects attended for a second interview about 4 months later. For both age at first sexual intercourse and number of sexual partners, intraclass correlation coefficients were high, ranging from 0.94 to 0.98. Repeatability differed a little by human papillomavirus status, but not by levels of other relevant factors.

Factors Influencing Basophilic Differentiation of HL-60 Cells

Lineage-specific hematopoietins apparently act in concert with multipotent factors in an orderly sequence of growth and differentiation. We have used the human acute promyelocytic leukemia cell line HL-60 to examine basophilic differentiation, using radioenzymatic assay of histamine content as an end point. Recombinant human interleukin 1 (rhIL-1), rhIL-2, rhIL-4, and recombinant human alpha and gamma interferons did not stimulate basophilic differentiation either in the presence or absence of sodium butyrate, an important cofactor for induction of differentiation. In contrast, rhG-CSF (granulocyte colony-stimulating factor), rhGM (granulocyte-macrophage) CSF, rhIL-3, rhIL-5, nerve growth factor, conditioned medium (CM) from the hairy T cell leukemic line Mo, and nasal polyp epithelial CM stimulated significant increases in histamine content in HL-60 cells at day 5 in vitro. GM-CSF did not account for all of the basophilic differentiating activity in Mo-CM. The data suggest that a unique, lineage-specific, basophilic cell differentiation factor is produced by T cells and point to the possible diagnostic and therapeutic relevance of in situ hematopoietic mechanisms in human respiratory disease.

Epstein-Barr Virus in Non-Hodgkin's Lymphomas and Lymphoid Tissue in Children

In developed countries the majority of adolescent children show serological evidence of past Epstein-Barr virus (EBV) infection. This virus is associated with non-Hodgkins lymphomas in immunocompromised children, but the relationship of EBV DNA to these tumors in children without documented immunodeficiency has not been investigated by the polymerase chain reaction (PCR). We used a PCR method with primers from the Bam W and Bam HI regions to study non-Hodgkins lymphomas in children, with tonsillar tissue of age-matched children as controls for the presence of EBV DNA. Six of the 20 tonsils were positive using the Bam W primers; another four showed this DNA with Bam HI primers. EBV DNA was detected in only one tumor (a lymphoblastic lymphoma) by both primer sets. The demonstration of EBV DNA in the tonsils reflects past infections and the incidence is in accordance with that expected from serologic epidemiological studies. The absence of demonstrable EBV DNA in 19 lymphomas suggests that this virus is of little consequence in the pathogenesis of non-Hodgkins lymphomas in children who are not known to be immunocompromised. The lymphoblastic lymphoma had a mixed cell population, and the virus was not necessarily related to the malignancy.

ANALYSIS OF PICHINDE ARENAVIRUS TRANSCRIPTION AND REPLICATION IN HUMAN THP-1 MONOCYTIC CELLS

Human promonocytic THP-1 cells were previously shown to be nonpermissive for Pichinde virus (PV) replication unless the cells were induced to differentiate to macrophages by stimulation with phorbol ester (PMA) (J. Virol. 65, 3575, 1991). The restriction did not involve receptor modulation, virus binding, nor internalization of virus but a requirement for a host cell function in PV replication was observed in that the phorbol ester effect required protein kinase C activation and was inhibited by actinomycin D. In this report we demonstrate that PV S RNA genomes, antigenomes, GPC mRNA and NP mRNA are expressed at high levels in PMA treated THP-1 cells but at significantly lower levels or not at all in untreated cells. We have also determined that degradation of input viral S RNA does not account for decreased PV RNA synthesis in the undifferentiated cells. This suggests that the restriction of PV replication in THP-1 cells is a post-penetration event which precedes transcription of viral mRNAs and replication of viral genomes and supports a role for differentiation-specific host cell factors early in PV replication.

Assessment of the specificity of cytotoxic T lymphocytes for the nucleoprotein of Pichinde virus using recombinant vaccinia viruses.

SummaryPichinde virus (PV) infection of mice results in induction of a strong H-2 restricted, virus-specific cytotoxic T lymphocyte (CTL) response and rapid clearance of the virus. To define the specificities of CTL induced by PV infection, we constructed vaccinia virus recombinants containing cloned cDNAs corresponding to full-length (VVNP) and a truncated form (VVNP51–561) of the nucleoprotein (NP) gene of PV. Radioimmunoprecipitation analysis of infected cell lysates indicated that VVNP expressed a PV-specific product identical in size to that of authentic NP, while vaccinia virus recombinants containing truncated NP produced a polypeptide consistent with the synthesis of amino acids 51–561 of Pichinde virus NP. Interestingly, cells infected with VVNP synthesized easily detectable, but much lower levels of nucleoprotein relative to both PV and VVNP51–561. Primary virus-specific CTL induced in three different strains of inbred mice following intravenous infection with PV were able to lyse syngeneic target cells infected with PV but did not markedly lyse syngeneic targets expressing full-length or truncated NP following recombinant vaccinia virus infection. Similarly, secondary anti-PV specific CTL generated following in vitro restimulation by PV or selectively restimulated with vaccinia recombinants did not significantly lyse target cells expressing NP. Further, infection of mice with VVNP and VVNP51–561 did not induce CTLs specific for PV and did not prime mice for the generation of memory anti-PV CTL in vivo. These results suggest that PV gene products other than NP, such as the GPC or L protein, contain the major target epitope(s) recognized by PV-specific CTL.

The nucleoprotein of Pichinde virus expressed by a vaccinia-Pichinde virus recombinant partially protects hamsters from lethal virus challenge

SummarySyrian hamsters, strain MHA/Lak, are susceptible to intraperitoneal infection with Pichinde virus and die from an overwhelming viremia. We have studied the ability of a vaccinia-Pichinde recombinant virus expressing amino acids 51-561 of the viral nucleoprotein (VVNP51-561) to protect from lethal Pichinde virus infection. Priming with VVNP51-561 significantly delayed mortality and increased final survival outcome after challenge with 2×103 pfu of Pichinde virus. This protection was not complete compared to priming with Pichinde virus in the footpad, which was not lethal and provided 100% protection. At a higher challenge dose of Pichinde virus, 2×104 pfu, immunization with VVNP51-561 delayed mortality but did not increase final survival. The partial protection correlated with an early but not late reduction in infectious virus in serum, kidney and liver, and infectious centers in the spleen. Thus the immune response generated by VVNP51-561 could initially control the infection, effectively reducing the virus inoculum. As the infection proceeded, virus replication could not be limited resulting in death in some hamsters. The partial protection did not appear to be mediated by anti-viral antibodies since these were not detected in the serum of VVNP56-561-immunized hamsters. This finding appears to support the hypothesis that in many arenavirus infections cellular immunity is central to viral clearance and protection from reinfection.