Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0021051 (immunodeficiency)
 71,517 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human immunodeficiency virus (HIV)-infected cells induce acid-labile interferon-alpha (al-IFN-alpha) in cultures of mononuclear cells from peripheral human blood. We have investigated the physiochemical properties of such preparations to elucidate the reasons for acid-lability of this IFN. Al-IFN-alpha is a mixture of both glycosylated and unglycosylated molecules as shown by separation on Concanavalin-A Sepharose. Acid-lability is associated only with glycosylated molecules. Upon chromatography of the glycosylated fraction on Sepharose coupled to IFN-alpha-specific antibody, the portion of the IFN that is retained and eluted with guanidine-HCl is acid-stable, whereas the excluded antiviral activity is acid-labile, and is partially neutralized by antibodies to either IFN-alpha or IFN-gamma. Also, upon further purification of the unglycosylated fraction on the same antibody column, all antiviral activity remains indistinguishable from conventional IFN-alpha. Reconstitution experiments showed that glycosylated material excluded from the anti-IFN-alpha column potentiates antiviral activity of the IFN that is specifically retained by the column. This potentiation is abolished by acid treatment. Similar results are obtained with al-IFN-alpha from the serum of acquired immunodeficiency syndrome (AIDS) patients, indicating that its acid-lability is also the consequence of an acid-labile component that is capable of enhancing the antiviral activity. The potentiation of antiviral activity obtained by combining recombinant preparations of IFN-alpha and IFN-gamma suggests that the cooperating molecule is IFN-gamma.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Acid lability is not an intrinsic property of interferon-alpha induced by HIV-infected cells. 128 11

The association of maternal-to-infant transmission of human immunodeficiency virus type 1 (HIV-1) with maternal p24 antigenemia was assessed in 86 HIV-1-infected mothers. We retrospectively examined serum or plasma samples collected in the peripartum period (delivery +/- 11 days; sd 16.89 days; range, delivery +/- 2 months). Immune complexes of p24 antigen and anti-p24 antibody were dissociated using acid hydrolysis (Method A, glycine-HCl buffer; Method B, HCl) in an attempt to increase the sensitivity of the test. The detection of HIV-1 p24 antigenemia in serum was increased from 23 of 86 (26.7%) to 37 of 82 (45.1%) following acid hydrolysis with Method A (chi square = 5.4, P = 0.02) and to 36 of 78 (46.1%) with Method B (chi square = 5.874, P = 0.015). Mothers of HIV-1-infected children were no more likely to have p24 antigenemia than mothers of seroreverted infants when untreated samples were assayed (7 of 23 vs. 10 of 48; chi square = 0.348, P = 0.55). Although acid hydrolysis increased the ability to detect p24 antigen, it did not enhance any association between p24 antigenemia and maternal-to-infant transmission of HIV infection: Method A, 9 of 23 in mothers of infected children vs. 21 of 45 in mothers of seroreverted children (chi square = 0.112, P = 0.738); and Method B, 9 of 22 in mothers of infected children vs. 18 of 42 in mothers of seroreverted children (chi square = 0.014; P = 0.907), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lack of predictive value of maternal human immunodeficiency virus p24 antigen for transmission of infection to their children. 140 85

A method for the purification of a truncated, biologically active human immunodeficiency virus type 1 (HIV-1) trans-activator (rTAT) from recombinant Escherichia coli is reported here. The purification steps utilized include mild extraction (French press), concentration by ammonium sulfate precipitation, chromatography in 8 M urea on an S-Sepharose fast-protein liquid chromatography column, and finally, resolution by C-4 reverse-phase high-performance liquid chromatography. After the final step, the rTAT is dried and stored under salt-free conditions. Amino acid compositional analysis and N-terminal sequence analysis confirm that the purified protein is rTAT. Unlike other methods reported for purification of recombinant HIV-1 trans-activator, our protocol uses urea instead of guanidine HCl. The rTAT is fully soluble in buffered solutions at concentrations exceeding 10 mg/ml, migrates as a single 14 kDa species on both sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE) and two-dimensional PAGE gels with a pI of 9.3 +/- 0.3. Additionally, the rTAT migrates as a monomer on size-exclusion chromatography columns under native conditions. Finally, purified rTAT exhibits trans-activator activity when introduced into appropriate reporter cells. Since rTAT is monomeric when tested by gel filtration, and yet exhibits biological activity, we conclude that the method of purification we have utilized is distinct from all other methods reported to date.
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PMID:Purification of an active monomeric recombinant HIV-1 trans-activator. 142 16

Serum and aqueous humor samples, collected from 14 clinically normal cats and 96 cats with clinical evidence of intraocular inflammation, were assayed with ELISA for Toxoplasma gondii-specific immunoglobulin M (IgM), T gondii-specific IgG, T gondii-specific antigens, total IgG, and total IgM. Additionally, serum was assayed with ELISA for feline leukemia virus p27 antigen and antibodies against the feline immunodeficiency virus as well as with an immunofluorescent antibody assay for antibodies against feline coronaviruses. Calculation of the Goldmann-Witmer coefficient (C-value) for the T gondii-specific antibodies detected in aqueous humor established the likelihood of local antibody production. Serologic evidence of present or prior infection by an infectious agent was found in 81.9% of the clinically affected cats from which serologic results were available (77/94 cats). Seropositive results for toxoplasmosis were found in 74.0% of the clinically affected cats. Anterior segment inflammation was found in 93.1% (81/87 cats from which information was available) of the clinically affected cats, most of which were older males. Toxoplasma gondii-specific antibodies were not detected in the aqueous humor of 6 seropositive, clinically normal cats. The C-values for aqueous T gondii antibodies were greater than 1 in 44.8% of the cats and greater than 8 in 24.0% of the cats. Response to treatment with clindamycin HCl was positive in 15/20 (75%) of the T gondii-seropositive, clinically affected cats treated with this drug. In 13/15 (86.7%) T gondii-seropositive, clinically affected cats having a C-value greater than 1, response to treatment with clindamycin HCl was positive.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enzyme-linked immunosorbent assays for the detection of Toxoplasma gondii-specific antibodies and antigens in the aqueous humor of cats. 142 23

The core structure of retroviruses, including the human immunodeficiency virus (HIV), consists of proteins that are initially synthesized as polyprotein precursors and then processed by a virally encoded protease yielding the mature core polypeptides. To obtain sufficient quantities of the purified HIV core precursor p55 for detailed studies, a segment of HIV DNA encoding the full length core precursor polyprotein p55 was expressed in Saccharomyces cerevisiae using a plasmid containing a constitutive galactose promoter. The expression of this DNA produced a protein with an estimated molecular size of 55,000, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE); this protein was immunoreactive to anti-HIV p24 antisera. Following cell lysis, freezing, and thawing, the expressed protein was an insoluble aggregate that served as the starting material for the purification process. Solubilization of the insoluble p55 with guanidine HCl followed by phenyl-Sepharose column chromatography and high performance liquid chromatography resulted in a preparation of p55 that was greater than 95% pure by SDS-PAGE, immunoreactive to anti-HIV core protein antibodies, and completely soluble in aqueous solution. The expressed p55 appeared to be myristoylated as evidenced by the incorporation of radiolabel following incubation of recombinant yeast cells with [3H]myristic acid; in addition the amino terminus of the final purified protein was blocked. Proteolytic digestion of purified p55 with synthetic HIV protease yielded the predicted amino- and carboxyl-terminal products; these were confirmed by amino acid sequence analysis. In contrast, digestion of purified p55 by the protease derived from the avian myeloblastosis virus resulted in fragments that were different in size from those produced by the HIV protease. The availability of the purified, full length water-soluble HIV core precursor will be useful in identifying agents that inhibit its processing by the HIV protease.
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PMID:Purification and characterization of human immunodeficiency virus (HIV) core precursor (p55) expressed in Saccharomyces cerevisiae. 266 48

The reverse transcriptase (RT) of the human immunodeficiency virus type 1 (HIV-1) is the major target for antiretroviral therapy of the acquired immunodeficiency syndrome (AIDS). While some inhibitors exhibit activity against most retroviral RTs, others are specific for the HIV-1 enzyme. To develop an animal model for the therapy of the HIV-1 infection with RT inhibitors, the RT of the simian immunodeficiency virus (SIV) was replaced by the RT of HIV-1. Macaques infected with this SIV/HIV-1 hybrid virus developed AIDS-like symptoms and pathology. The HIV-1-specific RT inhibitor LY300046.HCl, but not zidovudine [3'-azido-3'-deoxythymidine (AZT)] delayed the appearance of plasma antigenemia in macaques infected with a high dose of the chimeric virus. Infection of macaques with the chimeric virus seems to be a valuable model to study the in vivo efficacy of new RT inhibitors, the emergence and reversal of drug resistance, the therapy of infections with drug-resistant viruses, and the efficacy of combination therapy.
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PMID:Animal model for the therapy of acquired immunodeficiency syndrome with reverse transcriptase inhibitors. 754 97

To identify the minimal structural elements necessary for biological activity, the rigid tricyclic nucleus of the known human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) inhibitor tetrahydroimidazobenzodiazepinthione was subjected to systematic bond disconnection to obtain simpler structures. A rational selection and testing of modeled analogs containing these potential pharmacophoric moieties led to the discovery of a new series of nonnucleoside inhibitors of RT. The lead compound of this new PETT series of nonnucleoside RT inhibitors, N-(2-phenylethyl)-N'-(2-thiazolyl)thiourea (LY73497), was found to inhibit HIV-1 but not HIV-2 or simian immunodeficiency virus in cell culture at micromolar concentrations. This derivative was also found to inhibit HIV-1 RT. Through an integrated effort involving synthesis and molecular modeling, compounds with nanomolar potency against HIV-1 in cell culture were developed. In these studies, LY300046-HCl was identified as a potent nonnucleoside inhibitor of HIV-1 RT possessing favorable pharmacokinetic properties.
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PMID:The PETT series, a new class of potent nonnucleoside inhibitors of human immunodeficiency virus type 1 reverse transcriptase. 757 25

Protein folding conditions were established for human immunodeficiency virus integrase (IN) obtained from purified bacterial inclusion bodies. IN was denatured by 6 M guanidine.HCl-5 mM dithiothreitol, purified by gel filtration, and precipitated by ammonium sulfate. The reversible solvation of precipitated IN by 6 M guanidine.HCl allowed for wide variation of protein concentration in the folding reaction. A 6-fold dilution of denatured IN by 1 M NaCl buffer followed by dialysis produced enzymatically active IN capable of 3' OH end processing, strand transfer, and disintegration using various human immunodeficiency virus-1 (HIV-1) long terminal repeat DNA substrates. The specific activities of folded IN preparations for these enzymatic reactions were comparable to those of soluble IN purified directly from bacteria. The subunit composition and enzymatic activities of IN were affected by the folding conditions. Standard folding conditions were defined in which monomers and protein aggregates sedimenting as dimers and tetramers wree produced. These protein aggregates were enzymatically active, whereas monomers had reduced strand transfer activity. Temperature modifications of the folding conditions permitted formation of mainly monomers. Upon assaying, these monomers were efficient for strand transfer and disintegration, but the oligomeric state of IN under the conditions of the assay is determinate. Our results suggest that monomers of the multidomain HIV-1 IN are folded correctly for various catalytic activities, but the conditions for specific oligomerization in the absence of catalytic activity are undefined.
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PMID:Folding of the multidomain human immunodeficiency virus type-I integrase. 806 20

Simian immunodeficiency virus matrix protein has been crystallized from Tris-HCl buffer with polyethylene glycol and isopropanol as precipitants. The crystals belong to space group C2 with unit cell dimensions a = 69.9 A, b = 115.2 A, c = 32.5 A, beta = 108.1 degrees and diffract X rays to a minimum Bragg spacing of 2 A. These crystals appear suitable for a high resolution structure analysis.
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PMID:Crystallization and preliminary X-ray investigation of recombinant simian immunodeficiency virus matrix protein. 807 98

This study compared the number of patients with detectable human immunodeficiency virus (HIV) antigenemia after immune complex (IC) dissociation by established methods using either 0.5 NCl or 1.5 M glycine buffer. Without IC dissociation, HIV antigen was detected in 43% of patients. After dissociation, the HCl method detected only an additional 7% of patients (P = 0.09), while the glycine method detected an additional 34% (P < 0.001). However, care must be taken in setting the threshold of the standards, and confirmatory neutralization assays should be performed to ensure specificity of HIV antigen enzyme immunoassay after IC dissociation.
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PMID:Increased detection of human immunodeficiency virus antigenemia after dissociation of immune complexes at low pH. 831 13


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