Adjuvant activity of the heat-labile enterotoxin from enterotoxigenic Escherichia coli for oral administration of inactivated influenza virus vaccine.

Alternative strategies for vaccination against influenza that elicit both systemic antibody and mucosal IgA responses are needed to improve the efficacy in protection against infection. This study demonstrated that oral delivery of inactivated influenza vaccine with the heat-labile enterotoxin (LT) from enterotoxigenic Escherichia coli elicited the spectrum of humoral and cell-mediated responses in BALB/c mice critical for the protection and recovery from influenza virus infection. Coadministration of LT with oral influenza vaccine increased antiviral serum IgG and mucosal IgA responses compared with administration of oral influenza vaccine alone.

A human chromosome 12-associated 83-kilodalton cellular protein specifically binds to the loop region of human immunodeficiency virus type 1 trans-activation response element RNA.

trans activation of human immunodeficiency virus type 1 (HIV-1) involves the viral trans-activator protein (Tat) and a cellular factor(s) encoded on human chromosome 12 (HuChr12) that targets the trans-activation response element (TAR) in the viral long terminal repeat. Because nascent TAR RNA is predicted to form a secondary structure that specifically binds cellular proteins, we investigated the composition of the TAR RNA-protein complex for HuChr12-specific proteins. UV cross-linking of TAR RNA-nuclear protein complexes formed in vitro identified an 83-kDa protein in human cells and in a human-hamster hybrid cell containing only HuChr12.

TAR loop-dependent human immunodeficiency virus trans activation requires factors encoded on human chromosome 12.

The trans-activator response region (TAR) RNA in the human immunodeficiency virus type 1 (HIV-1) and HIV-2 long terminal repeat forms stem-loop secondary structures in which the loop sequence is essential for trans activation. We investigated how the HIV trans-activation mechanism encoded on human chromosome 12 relates to the TAR RNA loop-dependent pathway. DNA transfection experiments showed that trans activation in human-hamster hybrid cells with the single human chromosome 12 and human T-cell lines was highly dependent on the native sequences of the HIV-1 TAR loop and the HIV-2 5' TAR loop.

Human chromosome-dependent and -independent pathways for HIV-2 trans-activation.

Human immunodeficiency virus (HIV types 1 and 2) replication is controlled by the interaction of viral-encoded regulatory proteins and host cellular proteins with the viral long terminal repeat (LTR). The presence of HIV-1 and HIV-2 trans-activator proteins, tat1 and tat2, respectively, greatly increases viral gene expression from their homologous LTRs. It is unclear if the cellular factors that support tat1-directed trans-activation of the HIV-1 LTR are the same for tat2 trans-activation of the HIV-2 LTR.

Human chromosome 12 is required for elevated HIV-1 expression in human-hamster hybrid cells.

Host cell factors act together with regulatory genes of the human immunodeficiency virus (HIV) to control virus production. Human-Chinese hamster ovary hybrid cell clones were used to probe for human chromosomes involved in regulating HIV gene expression. DNA transfection experiments showed that 4 of 18 clones had high levels of HIV gene expression measured by both extracellular virus production and transactivation of the HIV long terminal repeat in the presence of the trans-activator (tat) gene.

Direct detection of HIV RNA expression in seropositive subjects.

The polymerase chain reaction (PCR) and reverse transcription were used to assess human immunodeficiency virus type 1 (HIV1) RNA expression in peripheral blood mononuclear cell samples from seropositive subjects. HIV RNA was detected from seropositive subjects who had no symptoms, lymphadenopathy syndrome, and acquired immunodeficiency syndrome. DNA PCR of the samples used for RNA extraction showed that seventeen of eighteen (94%) contained HIV proviral DNA.

Comparative studies of wild-type and cold-mutant (temperature-sensitive) influenza viruses: independent segregation of temperature-sensitivity of virus replication from temperature-sensitivity of virion transcriptase activity during recombination of mutant A/Ann Arbor/6/60 with wild-type H3N2 strains.

RNA 1 (see end of Summary) of a cold-adapted and temperature-sensitive (ts) influenza virus mutant A/Ann Arbor/6/60 has a different mobility from RNA 1 of wild-type (wt) A/Ann Arbor/6/60 when subjected to electrophoresis through acrylamide/agarose gels in the absence of denaturing agents. Detection of this lesion in RNA 1 of the mutant virus was dependent on the temperature of the gel during electrophoresis. Because RNA 1 is believed to code for a protein involved in virus-specific RNA synthesis we compared phenotypes of virion transcriptases in the wt and mutant viruses.

Antigenic relationships among influenza virua A neuraminidase (N2) antigens by immunodiffusion and postinfection neutralization tests.

The antigenic relationships among the neuraminidases of influenza A strains from 1957 to 1973 were examined by postinfection application of neuraminidase antisera. This procedure causes inhibition of virus spread and apparent neutralization. Neuraminidase (apparent) neutralization and neuraminidase inhibition tests with chicken antisera gave similar results.

A simple double immunodiffusion test for typing influenza viruses.

The identification of influenza virus type has traditionally been based on the characterization of internal nucleoprotein (NP) antigens by the complement fixation (CF) test. Because this test is complex and time-consuming, it is used only infrequently. In this report we describe a double immunodiffusion (DID) test, which is proposed as a replacement for the CF test for the typing of influenza viruses.