Host Cell Antigens Research Articles

Infection with respiratory syncytial virus enhances expression of native receptors for non-pilate Neisseria meningitidis on HEp-2 cells

Respiratory virus infections have been suggested to be predisposing factors for meningococcal disease. Respiratory syncytial virus (RSV) affects young children in the age range at greatest risk of disease caused by Neisseria meningitidis. It has been previously shown that glycoprotein G expressed on the surface of RSV-infected HEp-2 cells (a human epithelial cell line) contributed to higher levels of binding of meningococci compared with uninfected cells. The aim of the present study was to examine the effect of RSV infection on expression of surface molecules native to HEp-2 cells and their role in bacterial binding. Flow cytometry and fluorescence microscopy were used to assess bacterial binding and expression of host cell antigens. Some molecules analysed in this study have not been reported previously on epithelial cells. RSV infection significantly enhanced the expression of CD15 ( P<0.05), CD14 ( P<0.001) and CD18 ( P<0.01), and the latter two contributed to increased binding of meningococci to cells but not the Gram-positive Streptococcus pneumoniae.

The effect of cigarette smoke on adherence of respiratory pathogens to buccal epithelial cells

Smoking is associated with an increased risk of respiratory tract infection in adults. In children, exposure to cigarette smoke is a risk factor for respiratory tract infection and bacterial meningitis. Active smoking and passive exposure to cigarette smoke is also associated with carriage of some potentially pathogenic species of bacteria in both adults and children. The aims of the study were to determine the effect of active smoking on: (1) bacterial binding to epithelial cells; (2) expression of host cell antigens that act as receptors for some species; and (3) the effects of passive exposure to water-soluble components of cigarette smoke on bacterial binding. Flow cytometry was used to assess binding to buccal epithelial cells of the following species labelled with fluorescein isothiocyanate: Neisseria meningitidis, Neisseria lactamica, Streptococcus pneumoniae, Bordetella pertussis, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus. Flow cytometry was also used to assess expression of host cell antigens which have been identified as bacterial receptors. For each species, binding to cells of smokers was significantly higher than to cells of non-smokers; however, expression of host cell antigens was similar on epithelial cells of both groups. Non-dilute cigarette smoke extract reduced binding of bacteria to epithelial cells, but dilutions between 1 in 10 and 1 in 320 enhanced binding. We conclude that smokers might be more densely colonised by a variety of potentially pathogenic bacteria. The enhanced bacterial binding to epithelial cells of smokers is not related to enhanced expression of host cell antigens that can act as receptors for some species, but possibly to components in the smoke that alter charge or other properties of the epithelial cell surface. Passive coating of mucosal surfaces with components of cigarette smoke might enhance binding of potentially pathogenic bacteria.

The effect of cigarette smoke on adherence of respiratory pathogens to buccal epithelial cells.

Smoking is associated with an increased risk of respiratory tract infection in adults. In children, exposure to cigarette smoke is a risk factor for respiratory tract infection and bacterial meningitis: Active smoking and passive exposure to cigarette smoke is also associated with carriage of some potentially pathogenic species of bacteria in both adults and children. The aims of the study were to determine the effect of active smoking on: (1) bacterial binding to epithelial cells; (2) expression of host cell antigens that act as receptors for some species; and (3) the effects of passive exposure to water-soluble components of cigarette smoke on bacterial binding. Flow cytometry was used to assess binding to buccal epithelial cells of the following species labelled with fluorescein isothiocyanate: Neisseria meningitidis, Neisseria lactamica, Streptococcus pneumoniae, Bordetella pertussis, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus. Flow cytometry was also used to assess expression of host cell antigens which have been identified as bacterial receptors. For each species, binding to cells of smokers was significantly higher than to cells of non-smokers; however, expression of host cell antigens was similar on epithelial cells of both groups. Non-dilute cigarette smoke extract reduced binding of bacteria to epithelial cells, but dilutions between 1 in 10 and 1 in 320 enhanced binding. We conclude that smokers might be more densely colonised by a variety of potentially pathogenic bacteria. The enhanced bacterial binding to epithelial cells of smokers is not related to enhanced expression of host cell antigens that can act as receptors for some species, but possibly to components in the smoke that alter charge or other properties of the epithelial cell surface. Passive coating of mucosal surfaces with components of cigarette smoke might enhance binding of potentially pathogenic bacteria.

Viral persistence: mechanisms and consequences

Recent research has brought additional information on how virus products interfere with host cell antigen processing in vitro, new information on the interaction of virus with dendritic cells as a mechanism for alteration of immune responses — especially immunosuppression, and a preliminary proposal that nonretroviral RNA viruses might persist by utilizing host—cell reverse transcriptase to enter a DNA phase of replication.

Hamster 2-cell embryos utilise the [formula omitted] antiporter to regulate intracellular pH

Persistence of Chlamydia trachomatis (C. trachomatis) in the joint is the most frequent cause of reactive arthritis following urogenital tract infection. The resulting changes of host cell antigen- and cytokine-expression are not precisely understood. We developed and evaluated a direct cytometric approach to visualize in vitro C. trachomatis-infected monocytes. Infectious elementary bodies (EBs) of C. trachomatis serovar K were labelled by incubation with 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester (CFSE). Afterwards, human peripheral blood monocytes were cultured with the CFSE-labelled EBs and analysed by flow cytometry. Real-time polymerase chain reaction (PCR) was used to demonstrate intracellular uptake and viability of CFSE-labelled C. trachomatis by the determination of gene expression. Labelling EBs with CFSE may become a valuable tool for studying the interaction between C. trachomatis and the host cell.

Construction of an antigenic map of the haemagglutinin-esterase protein of influenza C virus.

Four different antigenic sites (A-1, A-2, B-1, B-2) have been identified previously on the haemagglutinin-esterase (HE) glycoprotein of influenza C/Ann Arbor/1/50 virus with seven monoclonal antibodies (MAbs). In this study we produced 30 additional anti-HE MAbs, nine of which demonstrated at least one of the following activities: haemagglutination inhibition, receptor-destroying enzyme inhibition, haemolysis inhibition, and neutralization (group A). The remaining had none of these activities (group B). These antibodies, and those previously isolated, were used to construct a more complete antigenic map of the HE molecule. Operational and topological analyses showed that a minimum of nine non-overlapping or partially overlapping antigenic sites were present on the HE protein, five recognized by group A MAbs (A-1 to A-5) and four by group B (B-1 to B-4). Among these antigenic sites, site A-5 was unique in that MAbs to this site inhibited the receptor-destroying activity without influencing the receptor-binding activity, which supports the idea that the sites responsible for these two functions are separate. It was also found that several group B MAbs were cross-reactive with host cell antigens.

Anti-cellular Antibodies in Sera from Vaccinated Macaques Can Induce Complement-Mediated Virolysis of Human Immunodeficiency Virus and Simian Immunodeficiency Virus

Previous studies show that immunization of macaques with preparations of either human immunodeficiency virus (HIV) or simian immunodeficiency virus (SIV) that has been produced in human ceils can induce antibodies against both viral antigens and human cellular antigens. This is due to the fact that certain host cell antigens are carried along with the virus during the purification process. The current series of experiments were performed to determine whether these anti-cellular antibodies can activate complement and whether the resultant complement activation could lead to virolysis of either HIV or SIV. Sera from macaques immunized with SIV or HIV (produced in the H9 human cell line) contained anti-cellular antibodies as determined by flow cytometry. Antibodies in these sera were capable of activating complement on uninfected human cells. Sera from the HIV-immunized macaques induced complement-mediated virolysis of both HIV and SIV. Similarly, sera from SIV-immunized macaques induced complement-mediated virolysis of both SIV and HIV. These results suggested that anti-cellular antibody in the sera could induce complement-mediated virolysis of either virus. To investigate this further, sera was absorbed with uninfected cells, which removed all of the virolytic activity for the heterologous virus. These in vitro studies indicate that complement activation can be initiated by anti-human cell antibodies, and that this activation can result in the destruction either HIV or SIV. This unusual antiviral mechanism may account for some portion of the resistance of human cell-immunized macaques to human cell-produced SIV that has been recently reported.

合成ペプタイドを抗原として使用したＨＩＶ‐１，ＨＩＶ‐２抗体同時測定法の臨床的評価およびＨＩＶ‐１，ＨＩＶ‐２測定の交差反応について

The acquired immunodeficiency syndrome (AIDS) is caused by human immunodeficiency virus (HIV) that is possibly transmitted by blood transfusion, direct exposure to blood (and blood product) or through sexual contact, and in children, transmitted virtically from their infected mothers. It has been more and more important to detect HIV-1 in blood and plasma products. HIV-1 antibody has been measured by gelatin particle agglutination assay (PA), by enzyme immunoassay (EIA), and more confirmatively by western blot assay (WB).However, there become evident the presence of the second type of HIV, HIV-2, and recently the assay detecting both HN-1 and HIV-2 has become required.For this purpose, the HIV-1/2 antibody EIA and RPHA (red blood cell particle hemagglutination) tests were introduced.In this paper, we examined the sensitivity of UBI EIA-1/2, the immunoassay uniquely employing synthetic peptides for the detection of both antibodies. Our results showed that the use of these synthetic peptides offered the advantage of minimize the incidence of non-specific reactions caused by the antibody cross reactivities between virus antigens and the host cell antigens eluting from the cell lysate.

Development of monoclonal antibodies to PK‘X’, the causative agent of proliferative kidney disease

Abstract. Two monoclonal antibody probes were produced against PK'X’ cells. The parasites were partially purified by filtration and centrifugation of kidney tissue from rainbow trout with proliferative kidney disease and used as antigen for immunization of mice. The resulting monoclonal antibodies reacted with PK'X’ cell antigens in enzyme‐linked immunosorbent assay and immunohistochemistry tests. One antibody (Mab 12) appeared to be specific for PK'X’in kidney tissue, while the other (Mab 18) cross‐reacted with host cell antigens in the kidney tubules. These probes are invaluable tools for the investigation of parasite surface antigens and life cycle studies.

Modulation of cell surface molecules during HIV-1 infection of H9 cells. An immunoelectron microscopic study.

To study cell surface molecules and HIV-1 proteins on H9 cells 2 days after infection by immunogold electron microscopy, either in single or in double labelling using combinations of host cell-derived molecules and HIV-1 proteins. The presence of host cell antigens CD3, CD4 and human leukocyte antigen-DR (HLA-DR) and HIV-1 antigens gag p15, p17, p24 and env gp41 was evaluated using immunocytochemistry at the light microscopic level. H9 cells 2 days after infection were processed for conventional transmission electron microscopy and cryo-ultramicrotomy. Leukocyte antigens investigated were CD2, CD3, CD4 (two antibodies), CD5, CD8, CD25, CD30, CD63 antigens and HLA-DR; HIV-1-encoded antigens were gag p24, pol reverse transcriptase, and env gp41 and gp120. Double immunogold labelling was performed using reagents with different sized gold particles. For leukocyte markers, the labelling density of the cell membrane was assessed quantitatively on uninfected and infected H9 cells. Infected cells revealed the presence of gag p24, pol, and env gp41 and gp120 antigens on HIV-1 virions. Uninfected H9 cells showed a random distribution of cell surface molecules, including CD4 antigen, along the plasma membrane. The CD63 antigen, a lysosomal membrane glycoprotein, was located mainly in the cytoplasm of uninfected cells. Cells 2 days after infection showed CD4 labelling on sites where virions were budding from or attached to the cell surface and on free virions. Virions also showed labelling by CD3, CD5, CD25, CD30 and CD63 antibodies and anti-HLA-DR. Compared with uninfected cells, a significantly lower density was found on infected cells in labelling for CD4, CD5 and anti-HLA-DR. A significantly higher density on cells 2 days after infection was seen in CD63 labelling. During the first phase of infection host cell molecules concentrate on budding structures and newly generated HIV-1 virions. This phenomenon might contribute to the disappearance of these molecules (like the CD4 molecule) from the cell membrane after infection.

A human monoclonal autoantibody isolated from a patient with infectious mononucleosis reactive with both self antigens and Epstein-Barr virus nuclear antigen (EBNA)

In order to investigate the mechanism(s) by which Epstein-Barr virus (EBV) induces the outcome of autoantibodies during infectious mononucleosis (IM), a human IgM (k) monoclonal antibody to cytoskeletal filaments of epithelial cells has been prepared by EBV transformation of peripheral blood B lymphocytes obtained from a patient with IM. The antibody was also found to react with smooth muscle of frozen sections of human stomach tissue by immunofluorescence, and with the Epstein-Barr nuclear antigen (EBNA) by an enzyme-linked immunosorbent assay. These findings demonstrate at the clonal level the epitope homology between host's cell antigens and EBV-encoded nuclear antigen, which might have relevance in EBV-induced autoimmunity.

Simultaneous triple-immunogold staining of virus and host cell antigens with monoclonal antibodies of virus and host cell antigens in ultrathin cryosections

The mechanism of intracellular maturation and sorting of herpes simplex virus type I glycoproteins is not known in details. To elucidate the intracellular sorting of viral glycoproteins and their possible interaction with the cytoskeleton, a method for simultaneous immunogold staining of three antigens in ultrathin cryosections is described. Each antigen is stained by an indirect technique using mouse monoclonal IgG as first layer, rabbit anti-mouse IgG as second and gold-conjugated goat anti-rabbit IgG as third layer antibody. After each staining cycle the sections are covered by methyl cellulose and exposed to paraformaldehyde vapour at 80 degrees C for 30 min. This destroys the free antigen combining sites of the second and the third layer IgG and abolish contaminating staining. Simultaneous triple-staining is documented with three mouse monoclonal antisera specific for 1) herpes simplex virus type 1 glycoprotein C, 2) glycoprotein D and 3) alpha- and beta-tubulin as primary antibodies. Labelling for virus glycoproteins was found in some Golgi vesicles and close to the cytoplasmic microtubules as well as on the cell surface and on intracytoplasmic and extracellular virus particles.

Morphogenesis and morphology of HIV. Structure-function relations.

Fine structure and antigenic make-up analysis of HIV were combined in a 2D model, from which functional aspects can be deduced. On the envelope 72 probably trimeric surface knobs (gp120) are connected to the virion via the transmembrane protein gp41. Gp120 is shed during ageing of the virion, but host cell antigens stay firmly anchored to the envelope. Underneath the envelope, p17 forms the matrix protein layer, while the capsid of the double cone shaped core is built up of p24. The relation between biochemical findings and morphogenesis and maturation of HIV as well as aspects of pathogenesis and vaccination are discussed.

Antiviral Cytotoxic T Lymphocyte Induction and Vaccination

In developing vaccines to counteract viral infections, it is important to produce reagents that engender the type of immune response best suited to provide protection and avoid immunopathology. Recovery from infection is the principal role of T cell immunity, and cells that recognize virus-infected cells (cytotoxic T lymphocytes) and kill them--often before new virus is replicated--represent a crucial component of the recovery process. The cytotoxic T lymphocytes are particularly important in situations where the load of infection is high. In this review the cells and mediators, as well as the viral and host cell antigens involved in antiviral induction of cytotoxic T lymphocytes, are discussed. Particular attention is paid to the importance of the intracellular pathway of processing taken by viral antigens and the outcome in terms of the recognition of cytotoxic T lymphocytes. The new types of vaccines--especially subunits, antiidiotypes, and recombinant viral vectors--are discussed in terms of their likely effectiveness at inducing cytotoxic T lymphocytes.

Isolation of a protein antigen from Coxiella burnetii

Antigens prepared from Coxiella burnetii, strain Frankfurt, phase II, propagated in persistently infected Buffalo Green Monkey (BGM) cell cultures were purified by guanidinium hydrochloride treatment and chloroform/methanol extraction. By ELISA analysis, chloroform/methanol residues (CMR) proved to be free of host cell antigens. The CMR were sensitive to trypsin, pronase E and proteinase K, as determined by absorption-kinetics of CMR suspensions at 600 nm and release of protein. Coomassie blue stained SDS Polyacrylamide gels of proteinase hydrolysates from CMR revealed only a single component of apparently 27,000 D. Silver stained gels, however, showed a second component of apparently 12,000 D. In contrast, from untreated native C. burnetii a large variety of proteins, most of them protease-sensitive, were released by detergents at low temperatures, but the 27,000 D component was only solubilized at 60–100°C. The 27,000 D component was obviously the major protein of CMR as well as of whole cells. Antigenicity of this 27,000 D protein could be demonstrated by agargel precipitation test, ELISA and immunoperoxidase techniques applying antisera raised against whole cells and against the extracted component. The component was also recognized in a dot immunobinding assay by sera from guinea pigs infected with cloned C. burnetii strain Nine Mile, phase I, thus indicating an important role of this antigen in C. burnetii specific immune response.

Follow-up report on 50 subjects vaccinated against herpes genitalis with Skinner vaccine.

Fifty subjects at risk of herpes genitalis received 109 immunizations with Skinner herpes vaccine and were assessed after a follow-up period of 4-48 months, representing a total follow-up period of 694 patient months. There was no evidence of contraction of herpes genitalis in 49 subjects. The risk of virus transmission and rate of contraction of disease was quantified by construction of two functions, namely a unit of exposure risk calculated per year (UYE) and standard contraction rate (SCR); in this study the SCR was 0.02. There was no evidence of significant side-effects from vaccination. Administration of Alhydrogel adjuvant with vaccine induced temporary granuloma formation in most subjects but was only detectable beyond 1 year of follow-up in one subject, in whom a painless swelling of 0.2 cm was detected 3 years after vaccination. There was no evidence of immunological reactivity to host cell or calf serum antigens in any of the subjects vaccinated.

Inhibition of Turkey Herpesvirus Replication by Anti-Cellular Serum

Quail embryo fibroblasts were used to investigate how rabbit and chicken antisera against chicken erythrocytes carrying different B alleles of the major histocompatibility antigens affect the neutralization of herpesvirus of turkeys (HVT). Although the neutralizing activities of these antisera were rather low, the HVT propagated in chicken embryo fibroblasts (CEF) from certain genotypic embryos was neutralized more by the antisera to the corresponding erythrocytes. After absorption of these antisera with homologous erythrocytes, the neutralizing activity of the absorbed sera was reduced slightly. These results reveal that the virion antigens of HVT might be partially associated with the host cell antigens of the fibroblast infected with the virus. The virus grown in these cells might incorporate the host cell antigens, including histocompatibility antigens, into the virion envelope.

Monoclonal antibody against an antigen selectively assembled into vesicular stomatitis virus virions from HeLa cells.

A mouse hybridoma cell line IIB9, secreting IgG2b antibody specific for a HeLa cell antigen, was obtained by fusion of a mouse myeloma cell line with spleen cells from mice immunized with purified VSV tsO45 mutant (defective in assembly of G protein) which had been reproduced at a non-permissive temperature in HeLa cells. The monoclonal antibody IIB9 was strictly specific for HeLa cells in two tests: (1) reaction with VSV or Chandipura virus phenotypically mixed with host cell antigen, (2) complement-dependent cytotoxicity test (51Cr-release).

Autoimmune Disease and Viral Infection

Publisher Summary This chapter discusses the mechanisms by which viruses induce autoimmune diseases. It discusses the models of viral-induced immunopathology and reviews the host antigens, which serve as targets in nervous system disease. The chapter highlights that the epidemiology of multiple sclerosis suggests a viral etiology, and the pathology is most consistent with an immunopathologic process. It discusses the interaction of virus with host cell antigens. In diseases, such as multiple sclerosis, post-infectious encephalomyelitis, Guillain-Barre Syndrome and polymyositis the target antigen has not been defined. In each case, viruses have been implicated in the pathogenesis of the disease. In myasthenia gravis, the target antigen has been identified, but the chain of events leading to the disease process has not been deciphered. The chapter also describes the presence of the Fc receptor in herpes infection, and indicates the possibility of a bystander effect in the pathogenesis of autoimmune disease.

Stimulation of host centriolar antigen in TC7 cells by simian virus 40: requirement for RNA and protein syntheses and an intact simian virus 40 small-t gene function.

Simian virus 40 (SV 40) stimulated a host cell antigen in the centriolar region after infection of African green monkey kidney (AGMK) cells. The addition of puromycin and actinomycin D to cells infected with SV40 within 5 h after infection inhibited the stimulation of the host cell antigen, indicating that de novo protein and RNA syntheses that occurred within the first 5 h after infection were essential for the stimulation. Early viable deletion mutants of SV40 with deletions mapping between 0.54 and 0.59 map units on the SV40 genome, dl2000, dl2001, dl2003, dl2004, dl2005, dl2006, and dl2007, did not stimulate the centriolar antigen above the level of uninfected cells. This indicated that an intact, functional small-t protein was essential for the SV40-mediated stimulation of the host cell antigen. Our studies, using cells infected with nondefective adenovirus-SV40 hybrid viruses that lack the small-t gene region of SV40 (Ad2+ND1, Ad2+ND2, Ad2+ND3, Ad2+ND4, and Ad2+ND5), revealed that the lack of small-t gene function of SV40 could be complemented by a gene function of the adenovirus-SV40 hybrid viruses for the centriolar antigen stimulation. Thus, adenovirus 2 has a gene(s) that is analogous to the small-t gene of SV40 for the stimulation of the host cell antigen in AGMK cells.