Presentation of HIV V3 loop epitopes for enhanced antigenicity, immunogenicity and diagnostic potential.

Objective: To evaluate the immunological properties of a panel of human mucin MUC1/HIV V3 loop chimeras.

Design: The immunodominant epitope of MUC1 (APDTR) was found to be structurally isomorphous with the tip of the principle neutralizing determinant (PND) of HIV-1 (MN) (GPGRA). A panel of 120 residue, six tandem repeat (TR) and 60 residue, three TR chimeric antigens were constructed in which the repeating MUC1 epitope is replaced by HIV-1 PND.

Oral fluid as a specimen for detection and confirmation of antibodies to human immunodeficiency virus type 1.

Paired serum and oral fluid specimens (n = 287) were collected with the Omni-Sal device and were assayed for the presence of antibodies to human immunodeficiency virus type 1 (HIV-1). Enzyme immunoassays (EIAs)--Abbott 3A11, an Organon Teknika Corporation research-use-only test, and the Murex GACELISA--were used per the manufacturers' inserts or were modified slightly to accommodate the oral fluid specimens. Compared with serum Western blot (immunoblot) results, each EIA had a sensitivity of 100% and the specificities were 89.

Human immunodeficiency virus (HIV) antigens: structure and serology of multivalent human mucin MUC1-HIV V3 chimeric proteins.

Molecular modeling and two-dimensional NMR techniques enable us to identify structural features in the third variable region (V3) loop of the human immunodeficiency virus (HIV) surface glycoprotein gp120, in particular the principal neutralizing determinant (PND), that remain conserved despite the sequence variation. The conserved structure of the PND is a solvent-accessible protruding motif or a knob, structurally isomorphous with the immunodominant knobs in the tandem repeat protein of human mucin 1 (MUC1) (a tumor antigen for breast, pancreatic, and ovarian cancer). We have replaced the mucin antigenic knobs by the PND knobs of the HIV MN isolate in a set of chimeric human MUC1/HIV V3 antigens.

Differential replication and pathogenic effects of HIV-1 and HIV-2 in Macaca nemestrina.

Objective: HIV-1 and HIV-2 isolates representing various geographic regions and distinct viral subtypes were examined for their ability to establish both in vitro and in vivo productive infections of Macaca nemestrina (pigtail macaque) peripheral blood mononuclear cells.

Methods: Animals were inoculated with either autologous cell-associated or cell-free viral preparations of selected isolates. HIV-specific immune responsiveness, hematologic changes, genetic variation, and virus burden were monitored as delineators of HIV pathogenesis.

Teratogenic effects of neonatal arenavirus infection on the developing rat cerebellum are abrogated by passive immunotherapy.

The effects of viral infection on the developing nervous system and the potential of passive immunotherapy to protect against infection were examined. When 4-day-old Lewis rats were injected intracerebrally with lymphocytic choriomeningitis virus (LCMV) the majority of stem cells within the external granular layer of the developing cerebellum became infected. The infection progressed to the molecular layer, internal granular layer, and the Purkinje cells.

Human immunodeficiency virus 1-specific IgA capture enzyme immunoassay for early diagnosis of human immunodeficiency virus 1 infection in infants. NYC Perinatal HIV Transmission Study Group.

A simplified human immunodeficiency virus 1 (HIV-1)-specific IgA capture enzyme immunoassay (IgA-CEIA) was evaluated and compared with IgA-Western blot assay for early diagnosis of HIV-1 infection in infants born to seropositive women. A total of 232 coded sera collected prospectively from 70 infants were tested. All 25 sera from 10 HIV-1-negative infants born to seronegative mothers (negative controls) were negative by both assays.

Dynamics of maternal IgG antibody decay and HIV-specific antibody synthesis in infants born to seropositive mothers. The NYC Perinatal HIV Transmission Study Group.

We have used a human immunodeficiency virus type 1 (HIV-1)-specific IgG-Fc capture enzyme immunoassay (IgG-CEIA) to elucidate the dynamics of HIV-1 maternal antibody decay and de novo synthesis of HIV-1 antibodies in infants. Two hundred and thirty-nine serum specimens from 77 infants were analyzed by the IgG-CEIA and by two different conventional EIAs. With the IgG-CEIA, IgG was captured by an anti-human IgG monoclonal antibody (3C8) that reacts with all subclasses and was detected by recombinant HIV-1 envelope protein (CBre3)-peroxidase conjugate.

Highly specific V3 peptide enzyme immunoassay for serotyping HIV-1 specimens from Thailand.

Objective: To develop and evaluate a simple V3 peptide-based enzyme immunoassay (EIA) for large-scale serotyping of HIV-1 specimens from Thailand.

Design: Serologic reactivities with synthetic peptides derived from the V3 loop of gp120 were used for typing HIV-1 specimens.

Methods: Synthetic peptides PND-A and PND-B, derived from the consensus amino-acid sequences of the V3 loop of gp120 from two major genomic variants of HIV-1 in Thailand (A and B), were evaluated in an EIA on 61 Thai HIV-1 sera for which genotypes had been determined by polymerase chain reaction.

Evaluation of testing algorithms following the use of combination HIV-1/HIV-2 EIA for screening purposes.

The licensure of combination human immunodeficiency virus type 1 and type 2 (HIV-1/HIV-2) enzyme immunoassays (EIAs) by the Food and Drug Administration has been accompanied by a recommendation that U.S. blood banks begin testing the nation's blood supply for HIV-2 by June 1, 1992.

Factors influencing HIV-1 banding patterns in miniaturized western blot testing of dried blood spot specimens.

In the HIV Seroprevalence Survey among Childbearing Women (SCBW), antibodies to human immunodeficiency virus type 1 are detected using enzyme immunoassays (EIA) and Western blot (WB) methods modified to accommodate samples of blood dried on special collection paper. Dried blood spot (DBS) eluates positive by EIA are tested by one of two WB methods, the miniblot technique using equipment from Immunetics Corporation and the PBS Integra assay (pageblot) from Genetic Systems. In this report we compared the performance of the two WB methods.

Prevalence of HIV-1 and HIV-2 mixed infections in Côte d'Ivoire.

We have investigated the cause of dual serological reactivity to human immunodeficiency virus (HIV) types 1 and 2, a common occurrence in West Africa. Serum specimens from 111 individuals from Côte d'Ivoire classified by commercial western blot as HIV-1 (n = 15), HIV-2 (32), and dually reactive (64) were further tested by more specific serological tests (a synthetic peptide enzyme immunoassay [Pepti-LAV 1/2] and western blots prepared from antigen in which oligomeric forms of the transmembrane protein were disrupted by trichloroacetic acid [WB-TCA]). Peripheral blood mononuclear cells were tested for HIV-1 and HIV-2 with the polymerase chain reaction (PCR) and virus culture.

Simian immunodeficiency virus needlestick accident in a laboratory worker.

The macaque monkey infected with simian immunodeficiency virus (SIV) is an animal model of the acquired immunodeficiency syndrome. We investigated a laboratory worker who was exposed by needlestick accident to blood from an SIV-infected macaque. Seroreactivity to SIV developed within 3 months of exposure, with antibody titres peaking from the third to the fifth month and declining thereafter.

Lack of correlation between maternal antibodies to V3 loop peptides of gp120 and perinatal HIV-1 transmission. The NYC Perinatal HIV Transmission Collaborative Study.

Recent reports have suggested that maternal antibodies to specific epitopes of the variable region 3 (V3 loop) of gp120 of HIV-1 might protect against perinatal transmission. In an attempt to confirm these findings, sera from 34 HIV-1-seropositive mothers, representing 13 episodes of mother-to-infant transmission and 23 episodes of non-transmission (two mothers had two pregnancies each during the study period), were tested for the presence of antibodies to various regions of the gp120 V3 loop. Synthetic peptides were generated from HIV-1MN.

Oligomeric nature of transmembrane glycoproteins of HIV-2: procedures for their efficient dissociation and preparation of Western blots for diagnosis.

Western blot (WB) analysis of various strains of HIV-2 indicated that transmembrane glycoprotein (TMP) of HIV-2 exists as trimers. These trimers have molecular weights and electrophoretic mobilities in the region of the major external glycoprotein, gp120, resulting in WB misidentification during diagnosis. A simple and rapid procedure was developed using trichloroacetic acid (TCA) to efficiently dissociate oligomeric forms of the TMP to monomers prior to the preparation of WB.

Imaging tumors with respect to a grid coordinate system by proton magnetic resonance using lipid suppression and T2 weighting.

Experimental tumors can be located with respect to a grid coordinate system by using lipid-suppressed T2-weighted proton imaging with thick coronal slices and a plexiglass grid containing a solution of paramagnetic ions. Most normal tissues except the brain, eyes, and CNS are essentially transparent under these conditions, allowing thick sections to be rapidly searched for tumors. Use of this approach to monitor tumor growth is demonstrated.

High efficiency immunoaffinity purification of anti-peptide antibodies on thiopropyl sepharose immunoadsorbants.

Antibodies to peptides are routinely made by immunizing animals with peptide linked to a carrier protein such as keyhole limpet hemocyanin (KLH) or bovine serum albumin (BSA) via a disulfide bond. The majority of such a polyclonal antibody response is directed against the carrier protein. The presence of such background antibodies often complicates efforts to characterize the desired anti-peptide antibody; hence it is desirable to isolate the specific fraction of immunoglobulin reactive against the peptide of interest.

Enhanced proton magnetic resonance imaging of experimental mammary tumors.

The proton magnetic resonance imaging contrast of experimental mammary tumors in rats has been dramatically improved. The technique developed combines T2 weighting and chemical-shift imaging in order to suppress the thoracic wall, muscle, and subcutaneous fat contributions to the image. The technique is demonstrated using the R3230AC mammary adenocarcinoma in F344 rats at 4.

Deuterium nuclear spin relaxation in biological tissues.

The deuterium nuclear spin relaxation times have been measured in tissues taken from rats given 20% deuterium oxide in their drinking water. The spin-lattice and spin-spin relaxation times were measured at 13.7 MHz by the inversion-recovery and Carr-Purcell-Meiboom-Gill FT methods, respectively.

Site-specific antibodies define a cleavage site conserved among arenavirus GP-C glycoproteins.

Arenaviruses share a common strategy for glycoprotein synthesis and processing in which a mannose-rich precursor glycoprotein, termed GP-C in lymphocytic choriomeningitis virus (LCMV), is posttranslationally processed by oligosaccharide trimming and proteolytic cleavage to yield two structural glycoproteins, GP-1 and GP-2. Mapping the orientation and proteolytic cleavage site(s) in such polyproteins has traditionally required direct protein sequencing of one or more of the cleaved products. This technique requires rigorous purification of the products for sequencing and may be complicated by amino-terminal modifications which interfere with sequence analysis.