PubMed Health⌕ Search

Biomedical subjects

F M Gotch

Publications and source records attributed to F M Gotch.

At least 55 records · Page 3Linked to original sources
PubMed1989

Recognition of the PB1, neuraminidase, and matrix proteins of influenza virus A/NT/60/68 by cytotoxic T lymphocytes.

We have investigated the recognition of the PB1, neuraminidase, and matrix (M1) proteins of influenza virus A/NT/60/68 (H3N2 subtype) by secondary in vitro stimulated polyclonal cytotoxic T lymphocyte (CTL) populations. While these three proteins have different functions and cellular locations, they can all be recognized as target antigens. However, the immunogenicity of these proteins for CTLs is under strict genetic control. Thus, PB1 protein is recognized as a cross-reactive target antigen by CTLs raised in CBA (H-2k) but not BALB/c (H-2d) mice. CBA, but not BALB/c mice, also generate a low-level CTL response to the neuraminidase. This latter response was only detectable following in vivo priming of CBA mice with a recombinant vaccinia virus expressing neuraminidase (N2-VACC). The matrix protein, expressed from recombinant vaccinia virus M-VACC, was not recognized as an antigen by CTL generated from either CBA or BALB/c strains of mice. By contrast, human HLA-A2-restricted influenza virus-specific CTLs were shown to recognize this matrix protein as a target antigen. Endogenous expression of as little as 90 amino acids of the matrix protein was sufficient to render target cells susceptible to lysis by such CTLs.

Animals↗
PubMed1988

Effect of mutations and variations of HLA-A2 on recognition of a virus peptide epitope by cytotoxic T lymphocytes.

Cytotoxic T lymphocytes (CTL) specific for influenza A virus were prepared from 15 donors. Those with HLA-A2 recognized autologous or HLA-A2-matched B-lymphoblastoid cells in the presence of synthetic peptide representing residues 55-73 or 56-68 of the virus matrix protein sequence. Influenza A virus-specific CTL from donors without HLA-A2 or with an HLA-A2 variant type failed to respond to this peptide. CTL lines specific for HLA-A2 plus peptide did not lyse peptide-treated target cells from HLA-A2 variant donors. They also failed to lyse peptide-treated cells with point mutations that had been inserted into HLA-A2 at positions 62-63, 66, 152, and 156 and, in some instances, mutations at positions 9 and 70. CTL lysed peptide-treated target cells with mutations in HLA-A2 at positions 43, 74, and 107. The results imply that this defined peptide epitope therefore interacts with HLA-A2 in the binding groove so that the long alpha-helices of HLA-A2 make important contact with the peptide at positions 66, 152, and 156. Different amino acids at position 9, which is in the floor of the peptide binding groove of HLA-A2 and the closely related position 70, modulate the peptide interaction so that some T-cell clones react and some do not.

Antigen-Antibody Complex↗
PubMed1986

HLA B37 determines an influenza A virus nucleoprotein epitope recognized by cytotoxic T lymphocytes.

Human influenza A virus-specific, cytotoxic T cells have been shown previously to recognize the virus nucleoprotein on infected cells. CTL preparations from four HLA B37-positive donors were shown to recognize a synthetic peptide that corresponded to amino acids 335-349 of the nucleoprotein sequence. Influenza-specific CTL from 10 donors of other HLA types failed to recognize this epitope. CD8+ CTL lines were derived from lymphocytes of two HLA B37-positive donors and used to show that the peptide was represented on virus-infected cells and to determine the probable boundaries of the epitope.

Cell Line↗
PubMed1986

The epitopes of influenza nucleoprotein recognized by cytotoxic T lymphocytes can be defined with short synthetic peptides.

A proportion of cytotoxic T lymphocytes (CTL) responding to infection by influenza recognize target cells that express the viral nucleoprotein. Recent work showed that CTL can recognize short overlapping regions of large nucleoprotein fragments expressed in transfected L cells. This led to the suggestion that CTL recognize segmental epitopes of denatured or degraded proteins in a similar way to helper T cells. One corollary of this idea is that CTL should recognize appropriate short peptides on the target cell surface. We demonstrate that the epitopes of nucleoprotein recognized by CTL in association with class I molecules of the major histocompatibility complex in both mouse and man can be defined with short synthetic peptides derived from the nucleoprotein sequence.

Alleles↗
PubMed1986

Recognition of influenza A virus nucleoprotein by human cytotoxic T lymphocytes.

A recombinant vaccinia virus (NP-VAC) containing cDNA corresponding to segment 5, the nucleoprotein (NP) gene of influenza A/PR/8/34 virus was used to examine the specificity of human influenza virus immune cytotoxic T lymphocytes (CTL). Effector cell preparations from two donors recognized autologous lymphocytes that had been infected with NP-VAC. Lysis was specific because cells infected with vaccinia virus were not killed and recognition was HLA-restricted. In one donor, the influenza virus-specific CTL response changed with time so that his effector cells no longer recognized autologous lymphocytes infected with NP-VAC. However, a component that was NP-specific remained because these CTL lysed the more sensitive autologous B lymphoblastoid cells that had been infected with NP-VAC. In four other donors, no NP-specific CTL response could be detected using autologous lymphocyte targets. Thus NP, an internal virus protein, is one antigen that is recognized by human influenza A virus-specific CTL, but it is likely that other individual virus components contribute to the total CTL response.

Cytotoxicity, Immunologic↗
PubMed1985

Effects of monoclonal antibodies to the alpha and beta chains of the human lymphocyte function-associated (H-LFA-1) antigen on T lymphocyte functions.

The ability of two antibodies, one specific for the alpha chain, p180, and the other for the beta chain, p95, of the human lymphocyte function-associated (LFA-1) antigens, to inhibit T cell function was measured. Both antibodies inhibited T cell-mediated lysis of virus-infected target cells and of K562 cells. Only the anti-beta chain antibody inhibited natural killer cell lysis of K562. The antibodies inhibited cytotoxic T lymphocyte cell (CTL) lysis of HLA-mismatched target cells in the presence of concanavalin A at 6.25-12.5 micrograms/ml, but at higher doses of Con A no inhibition was seen. When the lytic process was divided into calcium-independent (adherence) and -dependent (lysis) steps the antibodies were found to block at the initial step of conjugate formation. The effects of these antibodies on T cell proliferative responses showed that responses to antigens, alloantigens, mitogens and anti-CD3 (UCHT1) antibody were greatly inhibited. All of these responses are adherent cell dependent and proliferation of adherent cell-depleted mononuclear cells to Sepharose-coupled UCHT1 was not inhibited by anti-LFA-1 antibodies. Proliferation to paired anti-CD2 (T11) antibodies was also only weakly inhibited. Release of interferon-gamma by CTL on contact with target cells was also inhibited by anti-LFA antibody. These results are evidence that the LFA antigen is necessary for a nonspecific interaction with antigen-presenting cells that is essential for activation of T cells through the CD3-T cell receptor complex.

Antibodies, Monoclonal↗
PubMed1985

Characterization of the HLA-A2.2 subtype: T cell evidence for further heterogeneity.

Five blood donors were identified whose HLA-A2 is different from the common HLA-A2. Their A2 molecule (A2.2) had a more basic isoelectric point than normal A2 (A2.1). Cytotoxic T lymphocytes (CTL) restricted by HLA-A2.1, specific for influenza A and Epstein-Barr viruses, failed to lyse virus-infected target cells with HLA-A2.2. Identical patterns were obtained with both viruses. CTL from four of the A2.2-positive donors recognized target cells prepared from others in the group that shared only the HLA-A2.2 antigen. The A2.2 antigen from one donor seemed to be different in that target cells were not recognized by CTL from donors with the normal A2.1 nor with basic A2.2. There seems, therefore, to be heterogeneity within the HLA-A2.2 subtype.

Cytotoxicity, Immunologic↗
PubMed1985

Cytotoxic T cells recognize fragments of the influenza nucleoprotein.

Recent work has shown that a major population of murine influenza A specific cytotoxic T lymphocytes (CTL) recognize the viral nucleoprotein. In order to investigate the mechanism by which this nonglycoprotein component of the virus is recognized by CTL, a series of deletion mutants of an A virus NP gene were studied. The results showed that CTL recognize three distinct epitopes of the NP molecule. Both N- and C-terminal fragments of the protein are transported, independently of each other, to the site of recognition by CTL. These findings imply that a mechanism may exist for transport to the cell surface and presentation to CTL, of viral proteins and protein fragments that lack defined signal sequences.

Animals↗
PubMed1983

Declining T-cell immunity to influenza, 1977-82.

Influenza-A-virus-specific, HLA-restricted, cytotoxic T-cell immunity, measured in 189 volunteers in the six years 1977-82, showed a sharp decline from 1978. It is shown that natural infection with influenza-A virus boosts cytotoxic T-cell memory. The decline in T-cell immunity is probably associated with the low prevalence of influenza-A-virus infection since 1978.

Adolescent↗
PubMed1983

Cytotoxic T-cell immunity to influenza.

In a study designed to determine whether cytotoxic T lymphocytes contribute to immunity against influenza virus infection, we inoculated 63 volunteers intranasally with live unattenuated influenza A/Munich/1/79 virus. Over the next seven days clinical observations were made, and the amount of virus shed was measured. The protective effects of preinfection serum antibody and of cytotoxic T-cell immunity against influenza A virus were assessed for each participant. All subjects with demonstrable T-cell responses cleared virus effectively. This response was observed in volunteers in all age groups, including those born after 1956, who did not have specific antibody and hence had probably not been exposed to this subtype of influenza A virus before. Cytotoxic T cells show cross-reactivity in their recognition of the different subtypes of influenza A virus, in contrast to the antibody response that is specific for each virus subtype. We conclude that cytotoxic T cells play a part in recovery from influenza virus infection.

Adolescent↗
PubMed1983

A human lymphocyte-associated antigen involved in cell-mediated lympholysis.

Human lymphocyte function antigen (HLFA) is a cell surface protein defined by two monoclonal antibodies MHM23 and MHM24. It is present on both B and T lymphocytes but in greater amounts on the latter. Both antibodies precipitated antigen, from radiolabeled HSB-2 cells, which ran as two chains on sodium dodecyl sulfate polyacrylamide gel electrophoresis at 180 and 94 kDa. Neither antibody inhibited binding of the other, indicating that distinct epitopes were recognized. Both antibodies were shown to inhibit HLA-restricted lysis of influenza virus-infected and Epstein-Barr virus-transformed target cells by cytotoxic T lymphocytes. Blocking occurred at the level of the effector cells and in the presence of subsaturating concentrations of antibody. Both reagents also inhibited lysis of K562 cells, mediated by natural killer cells. These blocking effects differ from the inhibitory effects of monoclonal anti-HLA ABC and anti-suppressor cytotoxic T cell antibodies which inhibit only HLA-restricted lysis when present in saturating amounts. It is concluded therefore that HLFA is likely to be involved in the nonspecific adherence or lytic functions of killer cells rather than specific antigen recognition.

Antibodies, Monoclonal↗
PubMed1983

Plasma membranes from influenza virus-infected cells induce in vitro human secondary virus-specific cytotoxic T lymphocyte responses.

Influenza A virus-specific cytotoxic T lymphocytes (CTL) were induced by incubating human peripheral blood mononuclear cells with membranes prepared from influenza A virus-infected cells. The response obtained was equivalent to that given after sensitization in vitro with influenza A virus-infected lymphocytes. It was shown that this response was only obtained when stimulating membrane fragments and responding cells shared HLA-A or -B locus antigens. In order to analyse further the nature of the activating antigen, the membrane fragments were solubilized with detergent and then reconstituted by dialysing it out. This treatment destroyed their ability to stimulate virus-specific CTL although similar treatment of membranes from uninfected cells did not affect their capacity to stimulate a xenogeneic mouse CTL response. Liposomes constructed to contain defined virus and cell surface antigens also failed to stimulate CTL. These findings suggest that secondary induction of influenza virus-specific CTL in vitro requires the presence of the correct HLA antigen and that the virus-membrane association is irreversibly destroyed by detergent treatment.

Animals↗
PubMed1982

Lysis of allogeneic human lymphocytes by nonspecifically activated T-like cells.

In the generation of cytotoxic effector cells specific for influenza A virus-infected lymphocytes, three donors have given an unusual pattern of lytic activity, killing HLA-mismatched target cells. This has been analyzed in detail for one donor and one of the other two shows similar results. Activation only requires culture in medium between 1 and 4 days and parallels development of cell line K562-directed natural killer cells. Target lymphocytes do not need to be virus-infected and appear to be normal lymphocytes. The effector cells carry the surface markers T3 and T8 defined by OKT3/anti-Leu4 and OKT8/anti-Leu2a monoclonal antibodies, respectively. Unlike HLA class 1-restricted or -directed cytotoxic T cells, neither anti-Leu2a/nor anti-Leu4 blocked killing in the absence of complement. MHM23, a monoclonal antibody specific for the human lymphocyte function antigen, blocked lysis. The results indicate that these effector cells are related to cytotoxic T lymphocytes, but can lyse allogeneic target cells through a different recognition process. There is some specificity because autologous cells were not killed.

Antibodies, Monoclonal↗
PubMed1981

Neutrophil function in coeliac disease.

Neutrophil function of 23 patients with coeliac disease, consisting of 13 untreated and 10 on treatment with a gluten-free diet, was examined. The results obtained were compared with those from health volunteers. No significant differences were observed between the coeliac subjects and the control group in respect of the bactericidal ability of the polymorphs and the opsonic capacity of the serum.

Celiac Disease↗
PubMed1980

Limited specific T-cell mediated cytolysis in the absence of extracellular Ca2+.

Mouse lymphocytes sensitized either in vitro or in vivo with allogeneic cells were analysed for their cytolytic activity incomplete or Ca2+-deprived medium. The deprived medium was obtained by adding EGTA in excess of the molar Ca2+ concentration but not exceeding that of Ca2+ plus Mg2+. The cytolysis in complete medium was between five and thirty-fold greater in terms of lytic units, than that in Ca2+-deprived medium. This applied equally for effectors sensitized in vivo or in vitro although the overall lytic capacity of the former was greater. The cytolysis in Ca2+-deprived medium was judged to be Mg2+ dependent, as little or no cytolysis was seen if EDTA was added to cultures in a molar concentration exceeding that of Ca2+ plus Mg2+. Direct comparison of cytolysis in complete and deprived medium showed no difference between effectors in the two situations with respect to (a) adherence to nylon wool; (b) sensitivity to lysis by anti-Thy-1.2 antiserum and complement; (c) specificity of lysis; (d) rate of cytolysis with time when effector cell numbers were adjusted to give equal levels of cytolysis at any one time; and (e) shape and angle of the slope of 51Cr release against log increase in effector cell numbers where target cell numbers were constant.

Animals↗
PubMed1978

Analysis of synergy between cyclophosphamide therapy and immunity against a mouse tumour.

C3H/He and CBA/T6T6 mice which share the H2(k) haplotype were compared for their capacity to survive challenges with the C3H-derived fibrosarcoma BP8. It was found:(1) The tumour grows at the same rate with the same median survival time in matched groups of non-immunized mice from both strains after i.p. injection of tumour cells.(2) Cyclophosphamide (Cyclo) at 10 mg/kg will cure CBA mice which have received i.p. injections of 10(7) BP8, but this dose, and more intensive treatment with this drug, fails to cure C3H mice.(3) Injecting (125)IUdR-labelled tumour cells and counting (125)I loss by whole-mouse counting shows that the cytotoxic effect of Cyclo against BP8 is similar in the 2 mouse strains.(4) Cyclo itself does not cure CBA mice, for viable tumour cells are recoverable from the peritoneal cavity 10 days after CBA mice have received 10(7) BP8 followed by 10 mg/kg Cyclo.(5) CBA mice cured of BP8 ascites by Cyclo treatment will reject further i.p. inocula of BP8.(6) The strength of immunity induced by irradiated BP8 cells was directly related to the length of exposure to this antigen. An important aspect of Cyclo treatment is that it prolongs the period during which immunity may develop.(7) Immunization of CBA mice with heavily irradiated BP8, with or without Cyclo, failed to show that Cyclo depressed the capacity of CBA mice to develop cytotoxic immunity. There was some indication that animals immunized with irradiated cells plus drug did better than those with irradiated cells alone.(8) A single injection of irradiated BP8 cells into CBA mice induced weak cytotoxic immunity, as assessed by destruction of a subsequent challenge with BP8, but these mice died from tumour more rapidly than non-immunized controls. It is suggested from these data that immunological enhancement may not always be due to blocking of cytotoxic immunity.

Animals↗