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Biomedical subjects

A Malley

Publications and source records attributed to A Malley.

At least 19 recordsLinked to original sources
PubMed1998

Extracellular (soluble) antigen-specific T cell proteins related to the T cell receptor for antigen (sTCRr): serologic and primary amino acid sequence similarity to T cell receptor alpha chains and association with cytokines.

Antigen-specific-effected immunoregulation by T lymphocytes is mediated by extracellular proteins produced by T lymphocytes. These immunoproteins bind specifically to nonprocessed antigen and either induce antigen-specific immunoregulatory T cells (tsfi) or effect regulation (tsfe). T cell proteins that bind specifically to nonprocessed antigen have ben termed "T cell antigen-binding molecules" (TABM), and by definition, tsfe and tsfi are, in part, TABM. To characterize tsfi, tsfe, and TABM and understand the relationships and function of these immunoproteins, we have combined the efforts of two laboratories to compare tsfi, tsfe, and TABM isolated by each laboratory. Data obtained in one laboratory were reproduced by the other, and all reagents prepared by each laboratory were exchanged. TABM, tsfi, and tsfe were found to express TCRCalpha epitopes but not TCRCbeta epitopes. The amino acid sequence of a tryptic peptide of a T cell hybridoma TABM specific for nitrophenylhydroxy acetate (NP) is similar to a TCRalpha chain and TCR pre-alpha chain amino acid sequence. ELISA and immunoblotting demonstrated that Mr 77,000 T cell hybrid-derived tsfi, tsfe, and TABM are noncovalently associated with Mr 15,000-16,000 interleukin-10 (IL-10). ELISA also demonstrated that tsfi and tsfe are associated with I-J. The ability of tsfi and tsfe to suppress a mixed lymphocyte reaction was prevented by anti-IL-10 or anti-I-J antibodies, suggesting that antigen-specific immunoregulatory T cell proteins function by an antigen-specific focusing of immunoregulatory cytokines.

Amino Acid Sequence↗
PubMed1995

Stabilization and characterization of antigen-specific T suppressor inducer and T suppressor effector molecules.

H-2 specific T suppressor inducer (Tsfi) and T suppressor effector (Tsfe) factors show a dose-dependent inhibition of one-way mixed lymphocyte responses (MLR) between CBA/J responder spleen cells and C57BL/6 mitomycin C-treated stimulator spleen cells. The hydrophobic proteins Tsfi and Tsfe purified by ammonium sulfate precipitation and affinity methods were stabilized by the addition of Tris-saline pH 8 buffered octylglucopyranoside solution. The stabilized Tsfi and Tsfe fractions stored at 4 degrees C for 3-7 months retained a significant (> 72%) amount of their ability to inhibit MLR. Tsfi and Tsfe purified by salt precipitation and affinity methods were analyzed by SDS-PAGE. Enzyme-linked immunoassay (ELISA) and Western blots indicated that these molecules had T cell receptor (TcR) alpha chain, I-J, and IL-10 epitopes, but not TcR beta chain epitopes.

Animals↗
PubMed1994

Polymerase chain reaction detection of type D simian retrovirus proviral DNA from infected macaques.

A simple polymerase chain reaction (PCR) approach was developed for detection of Type D simian retrovirus (SRV) serogroup 2 proviral DNA using peripheral blood lymphocytes (PBLs) obtained from infected macaques. PCR primer pairs were developed against serogroup 2 envelope (env) gene sequence, and fidelity of PCR fragment amplification was determined using molecularly cloned SRV serogroup 2 (D2/RHE/OR) DNA, and genomic DNA from Raji cells independently infected with different SRV serogroups. One primer pair exhibiting high fidelity was then utilized for PCR detection of serogroup 2 proviral DNA from PBLs, and from cells sorted into immune cell subpopulations by fluorescent-activated cell sorting (FACS). Env PCR fragments were readily detected from as few as 10(4) PBLs or immune cell subpopulations. In addition, highly specific PCR primers against serogroups 1 and 3 were utilized to detect proviral DNA from Raji cells infected with SRV serogroups. In all cases, primers designed to amplify serogroups 1, 2, and 3 proviral DNA were specific for their intended serogroup. This primer information and development of a PCR approach for detection of specific SRV proviral DNA will be of potential utility as a rapid surveillance tool in monitoring type D simian retrovirus infection within Asian macaque colonies.

Animals↗
PubMed1994

Hypervariable epitope constructs as a means of accounting for epitope variability.

Epitope variability is one of the greatest obstacles to development of synthetic peptide vaccines. Based on a recently described hypervariable epitope (aa 414-434) on the envelope glycoprotein (gp130) to simian immunodeficiency virus (SIVmac142), we have developed a novel approach to account for epitope variability. We have prepared, in a single synthesis, a cocktail of peptides, designated a hypervariable epitope construct (HEC), which collectively represent all the in vivo variability seen in an epitope. The HEC represents permutations of amino acid substitutions found in the epitope and has been able to induce antibodies with enhanced binding to native SIV and broad immunoreactivity to related epitope analogues.

Amino Acid Sequence↗
PubMed1993

An epitope on the surface envelope glycoprotein (gp130) of simian immunodeficiency virus (SIVmac) involved in viral neutralization and T cell activation.

SIVmac infection of macaques is an important animal model for HIV infection and AIDS; this model is being utilized for development of antiviral therapies and vaccines. In the present article, we sought to identify neutralization epitopes of SIVmac envelope surface glycoprotein (gp130). Algorithms were used to predict antigenicity of specific regions. Four regions from the primary amino acid sequence of the viral surface glycoprotein were selected. A synthetic peptide representing one of these regions (414-434) induced virus-neutralizing antibodies in mice; in addition, this peptide induced T cell-proliferative responses in macaques. To address the in vivo relevance of these observations, we demonstrated that experimentally infected macaques produce antibodies to the neutralization epitope. In addition, rhesus macaques protected against infection by an inactivated SIV vaccine develop antibodies that bind to peptide 414-434. These observations demonstrate that the region that includes the sequence 414-434 in the fourth variable domain (V4) of SIVmac gp130 contains both a linear neutralization epitope and a T cell epitope.

AIDS Vaccines↗
PubMed1993

H-2-specific T suppressor cells. I. Evidence for T suppressor inducer and effector molecules in suppression.

The induction of H-2-specific Ts cells was accomplished by the i.v. injection of X-irradiated (2000R) C57BL/6 spleen cells into CBA/J mice. These Ts cells significantly (78%) suppressed the delayed type hypersensitivity (DTH) response in CBA/J mice injected s.c. with X-irradiated (2000R) C57BL/6 spleen cells and given a footpad challenge with the same cell population 5 days later. We have shown that both CD4 and CD8 T cells were involved in the observed suppression, and these cells secrete T suppressor inducer (Tsfi) and T suppressor effector (Tsfe) molecules. Both Tsfi and Tsfe molecules were shown to significantly inhibit (> 87%) one-way mixed lymphocyte responses between CBA/J and mitomycin C-treated C57BL/6 spleen cells. Using an adoptive transfer method, we showed that mice given both a primary and secondary immunization with X-irradiated C57BL/6 spleen cells to induce H-2-specific Ts cells contain a significantly greater number of Ts cells than mice given only a primary immunization, suggesting the presence of memory Ts cells.

Animals↗
PubMed1993

Auditing and accountability within the public hospital system: the need for structural reforms.

A recent report by the Independent Commission Against Corruption (ICAC) in NSW highlighted that some accounting controls for cash handling in public hospitals are inadequate. Given the number of public hospitals in Australia and the amount of cash being handled, it is essential that efficient accounting and auditing systems are established for these activities. This paper examines several major shortcomings in cash-handling methods used by NSW public hospitals and outlines how the system may be improved. The authors are currently developing a national survey to extend this analysis.

Accounting↗
PubMed1992

Privatisation in health care: theoretical considerations, current trends and future options.

Privatisation is once again back on the Australian political agenda. More significantly, privatisation has become an issue in the health care industry, following a proposal by the New South Wales government to privatise a public hospital in Port Macquarie. The main aims of this article are to discuss: the international move towards privatisation, the benefits of privatisation, the problems associated with privatisation in health care, and the potential health care services which could be privatised.

Australia↗
PubMed1991

Isolation and characterization of the neutralizable epitope of simian retrovirus-1 (SRV-1) and of the cell receptor for the virus.

An area encompassing residues 142-167 of the envelope protein of type D simian retrovirus (SRV-1) has been shown to contain the epitope to which neutralizing antibodies are directed. This area has been synthesized and shown to bind to monkey and mouse antiviral antibodies and to a virus neutralizing mouse monoclonal antibody. Protein conjugates of this peptide as well as the cross-linked or the free peptide induce antibodies capable of neutralizing, in vitro, viral infectivity. The cell receptor to the virus was isolated following extraction of Raji cells with non-ionic detergents. The receptor was isolated and characterized following radioimmuno-precipitation of 125I labeled cell extract bound to viral envelope protein. This immunoprecipitation could be inhibited by antiserum to peptide 142-167. Analysis in gels indicate that the receptor is of molecular weight of approximately 60 KDa. These results indicate that the neutralizing antibodies and the receptor recognize the same area on the viral envelope protein and that neutralization is the result of blocking the virus-receptor interaction by antibodies.

Amino Acid Sequence↗
PubMed1991

Immunobiological properties of a recombinant simian retrovirus-1 envelope protein and a neutralizing monoclonal antibody directed against it.

We previously reported that an area encompassing amino acids 147-162 of the envelope region of the simian (type D) retrovirus serotype 1 (SRV-1) constitutes an antigenic site for the binding of murine and rhesus neutralizing antibodies. Neutralizing antibodies to SRV-2 are directed to a different area, encompassing residues 96-102 of SRV-2. This paper presents data on the activity of an SRV-1 recombinant envelope protein (rEP) and of monoclonal hybridoma cell line, C11B8, produced from murine spleen cells immunized with SRV-1 rEP. Purified monoclonal antibodies from C11B8 bind to the SRV-1 rEP and to both SRV-1 and SRV-2. However, the monoclonal antibody exhibits strain specificity in the capacity to neutralize SRV-1 infection in vitro. Thus, C11B8 neutralizes SRV-1 infection but fails to neutralize four other known serotypes of the virus. C11B8 also binds to an SRV-1 synthetic peptide representing residues 142-167, which encompasses the previously defined antigenic site of recognition for neutralizing antibodies to SRV-1. This paper also contains evidence that the SRV-1 rEP construct binds the site for SRV-1 attachment to the cell receptor. This is indicated by the ability of SRV-1 rEP to compete with SRV-1 (but not with SRV-2) and inhibit its infectivity in vitro. In addition, SRV-1 rEP inhibits the neutralizing activity of C11B8 against SRV-1 infection in vitro. SRV-1 rEP has no inhibitory effect on rhesus neutralizing antibodies to SRV-2. Taken together, the above findings indicate that immunity conferred at the level of neutralizing antibodies during SRV infection is strain-specific and involves the recognition of envelope sequences unique to each strain.

Amino Acid Sequence↗
PubMed1991

The induction of neutralizing antibodies by synthetic peptides of the envelope protein of type D simian retrovirus-1 (SRV-1).

It has been recently demonstrated that two serotypes of type D simian retroviruses, namely SRV-1 and SRV-2, exhibit extensive immunological cross-reactivity but do not exhibit cross-reactivity at the level of neutralizing antibodies. We have also shown recently that an area which includes residues 147-162 of the envelope protein of SRV-1 constitutes an epitope to which neutralizing antibodies against SRV-1 but not against SRV-2 are directed. However, in spite of the capacity of various immunogenic preparations to induce antibodies which react with SRV-1 these antibodies were incapable of neutralizing in vitro viral infectivity. Work reported herein demonstrates that various immunogens consisting of a larger peptide, namely 142-167 of the envelope protein of SRV-1, induce antibodies capable of binding with the envelope protein of SRV-1 and with the whole virus. Moreover, these antibodies exhibit the capacity to neutralize in vitro the infectivity of SRV-1 but not of SRV-2.

Amino Acid Sequence↗
PubMed1991

Characterization of T- and B-cell epitopes of a simian retrovirus (SRV-2) envelope protein.

Synthetic envelope peptides of a simian retrovirus (SRV-2) were used to define both T- and B-cell epitopes of the envelope protein. The SRV-2 peptide 100-106 specifically blocks rhesus anti-SRV-2 neutralizing antibody activity, and a peptide 100-106 keyhole limpet hemocyanin conjugate induces a strong antipeptide antibody response. SRV-2 peptide 100-106 and 233-249 induces good T-cell proliferation of murine spleen cells immunized with the SRV-2 virus. Thus, SRV-2 envelope peptide 100-106 represents both a T- and B-cell epitope, and peptide 233-249 a T-cell epitope.

Amino Acid Sequence↗
PubMed1991

Neutralization epitope in the envelope glycoprotein of simian retrovirus-1 (SRV-1) and identification of the virus receptor.

We previously demonstrated that the area encompassing residues 147-162 of the envelope protein of simian retrovirus serotype-1 (SRV-1) is the target for rhesus anti-SRV-1 neutralizing antibodies. A peptide representing amino acids 142-167 of envelope protein (gp70) is capable of inducing virus-neutralizing antibodies in mice. The virus receptor was immunoprecipitated from Raji cells using gp70 as the ligand. Antibodies to peptide 142-167 inhibit the immunoprecipitation, indicating that the receptor recognizes residues 142-167 of the viral envelope protein.

Amino Acid Sequence↗
PubMed1990

Synthetic peptides of envelope proteins of two different strains of simian AIDS retrovirus (SRV-1 and SRV-2) represent unique antigenic determinants for serum neutralizing antibodies.

There are at least three distinct serotypes of simian type D retrovirus (SRV) which exhibit extensive serological cross-reactivity, but no cross-reactivity exists at the level of serum neutralizing antibodies. Amino acid sequence analysis and hydrophobicity plots of SRV-1 and SRV-2 envelope proteins were compared in order to identify unique potential antigenic determinants to which respective neutralizing antibodies may be directed. Peptides representing residues 147-162 of SRV-1 and 96-102 of SRV-2 were synthesized and assessed for their immunoreactivity. Free peptide inhibition of strain-specific serum (rhesus) neutralizing antibodies to SRV-1 and SRV-2 was demonstrated using the SRV-1 147-162 peptide and the SRV-2 peptide, 96-102, respectively. Inhibition of serum neutralizing activity by these peptides was also strain-specific, showing no cross-inhibition. SRV-1 147-162 conjugated to a protein carrier and cross-linked to Sepharose beads specifically adsorbed neutralizing antibodies from SRV-1 immune rhesus sera. The antibodies eluted from the immunoadsorbent possessed SRV-1 neutralizing activity, but showed no effect on the infectivity of SRV-2. Peptide SRV-1 147-162 also exhibited the capacity to bind specifically with a mouse monoclonal antibody which neutralizes the infectivity of SRV-1. Mice immunized with a recombinant SRV-1 envelope protein or with whole, inactivated SRV-1 produced antibodies which bound the SRV-1 147-162 conjugate, but not the protein carrier itself. Mouse antibodies to the SRV-1 147-162 conjugate exhibited specific binding with both native SRV-1 and with recombinant SRV-1 envelope protein. These findings provide strong evidence that SRV-1 147-162 and SRV-2 96-102 constitute at least two unique antigenic determinants, or parts thereof, which participate in the strain-specific neutralizing antibody response. Moreover, the findings indicate that the SRV-1 neutralizing antibodies produced by monkeys and at least a certain population of neutralizing antibodies produced by mice recognize the same epitope of SRV-1.

Amino Acid Sequence↗
PubMed1990

A monoclonal mouse anti-human IL-2 receptor antibody (anti-Tac) will recognize molecules on the surface of Xenopus laevis immunocytes which specifically bind rIL-2 and are only slightly larger than the human Tac protein.

We have made visible the binding of a mouse monoclonal anti-human interleukin 2 (IL-2) receptor (anti-Tac) antibody on the surface of phytohemagglutinin (PHA)-stimulated Xenopus thymocytes using a colloidal gold-conjugated goat anti-mouse antibody and transmission electron microscopy. No binding was found when a different mouse monoclonal antibody (mAb) of the same isotype and subclass was tested, or when the anti-Tac antibody was omitted from the procedure. After metabolic radiolabeling of the IL-2 receptors with [35S]methionine using PHA-stimulated thymocytes of Xenopus laevis, the South African clawed toad, we show that a concentrated preparation of the mouse anti-human Tac antibody will immunoprecipitate a radiolabeled molecule just slightly larger than 55 kDa. Phorbol dibutyrate (PDB), an effective T cell mitogen, and cyclosporin A, an inhibitor of T cell mitogenesis in this species, are both capable of regulating the expression of this IL-2-binding molecule on Xenopus immunocytes. Here, we use the calcium ionophore A23187 to show that the relationship between IL-2 receptor expression and mitogenesis, which was previously established in X. laevis, is associated with a calcium ion flux. Flow cytometry is used for assaying alterations in epitope expression after binding the lectin-stimulated cells under test with a fluorescence (Fl*) conjugate of the anti-Tac antibody or a control mAb, which is either anti-DNP or anti-keyhole limpet hemocyanin (KLH) in specificity, but of the same mouse isotype and subclass as the anti-IL-2 receptor antibody.

Animals↗
PubMed1989

The immune response of offspring mice from mothers immunized during pregnancy with protein antigens.

The immune system of offspring mice from mothers immunized with photo-oxidized timothy grass pollen antigen B (OX-AgB) or Trinitrophenyl-bovine gamma globulin (TNP-BGG) during their pregnancy was examined. Offspring mice immunized 6 or 8 weeks after delivery with the same antigen administered to their mothers have completely suppressed primary responses and greater than 80% suppressed secondary responses. The observed immunosuppression in offspring mice appears to persist until about 16 weeks after delivery, and is antigen-specific. Adoptive transfer studies show that spleen cells from adult OX-AgB primed mice injected i.v. into lethally X-irradiated (800 rads) syngeneic recipients and challenged with antigen produce significant levels of AgB-specific IgG antibody. Spleen cells (5 x 10(6] from offspring mice of mothers immunized with OX-AgB during their pregnancy were added to spleen cells from adult OX-AgB primed mice and injected i.v. into lethally X-irradiated syngeneic recipients and challenged with antigen. These recipients showed a significantly (greater than 85%) immunosuppressed secondary response. The observed immunosuppression appears to be mediated by CD4+ and CD8+ T cells suggesting a requirement for both T suppressor inducer and effector cell populations. The reported findings are discussed in relation to possible mechanisms to explain the immunosuppression obtained in the offspring of mothers immunized during pregnancy.

Animals↗