Coronavirus, Infection and Immunity

Encyclopedia of Immunology (Second Edition)
1998, Pages 658-661

HelmutWege

Abstract

The family of Coronaviridae was defined around 1968, primarily by morphologic criteria. The virions are pleomorphic to spherical-shaped particles (120–160 nm diameter), which are surrounded by a fringe of club- or pear-shaped surface projections (12–24 nm long; Figure 1). The virus has a lipid envelope and contains a single-stranded RNA genome of positive polarity. Coronaviruses infect humans, mammals and birds. Based on molecular criteria, the toroviruses represent a second genus within this family. Furthermore, evolutionary relationships to the Arteriviridae are discussed within the concept of a ‘coronavirus-like’ superfamily.

Keywords

Coronaviridae,  virions, coronavirus, Arteriviridae

Cellular composition, coronavirus antigen expression and production of specific antibodies in lesions in feline infectious peritonitis

Veterinary Immunology and Immunopathology
Volume 65, Issues 2–4, 23 October 1998, Pages 243-257

A. Kipar, S. Bellmann, J. Kremendahl, K. Köhler, M. Reinacher

Abstract

Twenty-three cats with spontaneous feline infectious peritonitis (FIP) were examined by light microscopy including immunohistology and histochemistry in order to determine the cellular composition and the expression of viral antigen in lesions in FIP. Furthermore, the presence of plasma-cells producing coronavirus-specific antibodies was evaluated in situ. Macrophages and neutrophils were demonstrated by an antibody against calprotectin (leukocyte protein L1, myeloid/histiocyte antigen), neutrophils were recognized due to their chloroacetate esterase activity, and B- and T-lymphocytes were identified by antibodies against the CD3 antigen and the CD45R antigen, respectively. Expression of viral antigen was immunohistologically demonstrated by a monoclonal antibody (mAb) against coronavirus while coronavirus-specific antibodies in situ were identified by the application of feline coronavirus prior to the coronavirus antibody. Lesions were classified as diffuse alterations at serosal surfaces, granulomas with areas of necrosis, granulomas without extended necrosis, focal and perivascular lymphoplasmocytic infiltrates, and granulomatous-necrotizing vasculitis. Diffuse alterations on serosal surfaces were represented either by activated mesothelial cells with single coronavirus antigen-bearing macrophages or by layers of precipitated exudate containing single to numerous granulomas with areas of necrosis. In liver and spleen, the exudate was often underlaid by a small band of subcapsular B-cells with an occasional plasma-cell producing coronavirus-specific antibodies. In other locations, a variably broad band of B-cells and plasma-cells, often infiltrating between underlying muscle fibers, separated the exudate from the unaltered tissue. Some of these plasma-cells were positive for coronavirus-specific antibodies. In granulomas with areas of necrosis, the central necrosis was surrounded by macrophages usually expressing considerable amounts of viral antigen. Few B-cells and plasma-cells were found in the periphery. In granulomas without extended necrosis, the number of macrophages were lower. Only few macrophages expressing low amounts of viral antigen were present. B-cells and plasma-cells formed a broad rim. Few plasma-cells stained positive for coronavirus-specific antibodies. In both types of granulomas, few neutrophils were found between macrophages. Few T-cells were seen scattered throughout the lesions. Focal and perivascular lymphoplasmocytic infiltrates were mainly seen in omentum and leptomeninx. B-cells were the predominant cells; some plasma-cells were positive for coronavirus-specific antibodies. Viral antigen was not readily detected in these alterations. Granulomatous-necrotizing vasculitis was occasionally found in kidneys and leptomeninx. It was dominated by macrophages which often stained strongly positive for coronavirus antigen. Different types of alteration were often seen in the same animal and even the same tissue. There was no obvious correlation between the cat's age, gross pathological changes, and the histological types of alteration. Single plasma-cells positive for coronavirus-specific antibodies were found around blood vessels distant from inflammatory alterations, within the lung parenchyma, as infiltrating cells in the mucosa of the small intestine, and in spleen and mesenteric lymph node. Results show that alterations in FIP are heterogeneous concerning cellular composition and expression of viral antigen. The dominance of B-cells in part of the lesions together with the presence of plasma-cells positive for coronavirus-specific antibodies indicate that these cells may play a role in the maintenance of inflammatory processes in FIP.

Keywords

Feline infectious peritonitis, Immunohistology, Coronavirus antigen, Coronavirus-specific antibodies, B-cells, Plasma-cells

Effects of the common cold on mood and performance

Psychoneuroendocrinology
Volume 23, Issue 7, October 1998, Pages 733-739

Andrew Smith, Marie Thomas, Julie Kent, Karl Nicholson

Abstract

Previous research has shown that both experimentally-induced and naturally occurring upper respiratory tract illnesses (URTIs) influence mood and mental functioning. None of the previous studies of naturally occurring colds has conducted appropriate virological assays to determine the nature of the infecting agent. This is an essential methodological step in studies of malaise associated with URTIs. The aim of this research was to investigate the effects of naturally occurring colds on mood and objective measures of performance. This was done by first conducting a cross-sectional comparison of 37 healthy people and 158 volunteers with colds and then a longitudinal study in which 100 volunteers developed colds and 87 remained healthy. Virological techniques were used to identify infecting agents and comparisons made across the different groups. The results showed that having a cold was associated with reduced alertness and slowed reaction times. These effects were observed both for colds where the infecting virus was identified and those where it was not. Similar effects were obtained for both rhinovirus and coronavirus colds. One may conclude that upper respiratory tract illnesses lead to a reduction in subjective alertness and impaired psychomotor functioning. This was true for both illnesses where the infecting agent was identified and for those clinical illnesses where no virus was detected. It is now important to identify the mechanisms linking infection and illness with the behavioural changes. Similarly, the impact of these effects on real-life activities such as driving needs examining. Finally, methods of treatment need to be developed which not only treat the local symptoms of the illnesses but remove the negative mood and the performance impairments.

Keywords

Common cold, Rhinovirus, Coronavirus, Reaction time, Alertness

Comparison of immunofluorescence with monoclonal antibodies and RT-PCR for the detection of human coronaviruses 229E and OC43 in cell culture

Journal of Virological Methods
Volume 72, Issue 2, June 1998, Pages 145-152

Jacques Sizun, Nathalie Arbour, Pierre J Talbot

Abstract

Human coronaviruses, with two known serogroups named 229E and OC43, cause up to one third of common colds and may be associated with serious diseases such as nosocomial respiratory infections, enterocolitis, pericarditis and neurological disorders. Reliable methods of detection in clinical samples are needed for a better understanding of their role in pathology. As a first step in the design of such diagnostic procedures, the sensitivities and specificities of two viral diagnostic assays were compared in an experimental cell culture model: an indirect immuno-fluorescence assay using monoclonal antibodies and reverse transcriptase-polymerase chain reaction amplification of viral RNA from infected cells. Immunofluorescence detected human coronaviruses in cells infected at a MOI as low as 10−2 (log TCID50/ml=4.25 for HCV-229E and 2.0 for HCV-OC43; log PFU/ml=4.83 for HCV-229E and 1.84 for HCV-OC43) versus 10−3 (HCV-OC43) or 10−4 (HCV-229E) for reverse transcriptase-polymerase chain reaction amplification (log TCID50/ml=1.75 for HCV-229E and 1.5 for HCV-OC43; log PFU/ml=2.3 for HCV-229E and 1.34 for HCV-OC43). There were no false positive signals with other human respiratory pathogens: influenza virus, respiratory syncytial virus and adenovirus. Moreover, each assay was coronavirus serogroup-specific. These results demonstrate the potential usefulness of immunofluorescence with monoclonal antibodies and reverse transcriptase-polymerase chain reaction RNA amplification for the rapid detection of human coronaviruses in infected cell cultures. Both methods could be applied to clinical specimens for the diagnosis of human infections.

Keywords

Coronavirus, 229E, OC43, Immunofluorescence, RT-PCR, Diagnostic

Roles in Cell-to-Cell Fusion of Two Conserved Hydrophobic Regions in the Murine Coronavirus Spike Protein

Virology
Volume 244, Issue 2, 10 May 1998, Pages 483-494

Zongli Luo, Susan R.Weiss

Abstract

The spike (S) protein of coronavirus, mouse hepatitis virus (MHV), mediates attachment and fusion during viral entry and cell-to-cell fusion later in infection. By analogy with other viral proteins that induce cell fusion the MHV S protein would be expected to have a hydrophobic stretch of amino acids that serves as a fusion peptide. Sequence analysis suggests that the S protein falls within the group of fusion proteins having internal rather than N-terminal fusion peptides. Based on the features of known viral fusion peptides, we identified two regions (PEP1 and PEP2) of MHV-A59 S2 as possible fusion peptides. Site-directed mutagenesis and an in vitrocell-to-cell fusion assay were used to evaluate the roles of PEP1 and PEP2, as well as a third previously identified putative fusion domain (PEP3) in membrane fusion. Substitution of bulky hydrophobic residues with charged residues within PEP1 affects the fusion activity of the S protein without affecting processing and surface expression. Similar substitutions within PEP2 result in a fusion-negative phenotype; however, these mutant S proteins also exhibit defects in protein processing and surface expression which likely explain the loss of the ability to induce fusion. Thus PEP1 remains a candidate fusion peptide, while PEP2 may play a significant role in the overall structure or oligomerization of the S protein. PEP3 is an unlikely putative fusion peptide since it is not conserved among coronaviruses and nonconservative amino acid substitutions in PEP3 have minimal effects on cell-to-cell fusion.

Keywords

cell-to-cell, coronavirus, mouse hepatitis virus, protein

In situ hybridization technique for the detection of swine enteric and respiratory coronaviruses, TGEV and PRCV, in formalin-fixed paraffin-embedded tissues

Journal of Virological Methods
Volume 56, Issue 2, February 1996, Pages 149-160

Theerapol Sirinarumitr, Prem S. Paul, John P. Kluge, Patrick G. Halbur

Abstract

The in situ hybridization (ISH) technique was developed to detect the swine coronaviruses, transmissible gastroenteritis virus (TGEV) and porcine respiratory coronavirus (PRCV), in cell culture and tissue sections from TGEV-or PRCV-infected pigs. The 35S-labeled RNA probes were generated from two plasmids pPSP.FP1 and pPSP.FP2 containing part of the S gene of TGEV. The procedure was first standardized in cell cultures. The radiolabeled pPSP.FP2 probe detected both TGEV and PRCV in virus-inoculated cell cultures, whereas pPSP.FP1 probe detected TGEV but not PRCV. The probe was then used to detect TGEV or PRCV in tissues of pigs experimentally infected with TGEV or PRCV or naturally infected with TGEV. Again, the probes detected TGEV in intestines of experimentally and naturally infected pigs and PRCV in the lungs of experimentally infected pigs. TGEV RNA was detected mainly within the enterocytes at the tips of villi and, less often, within some crypt epithelial cells. PRCV was shown to replicate mainly in the bronchiolar epithelial cells and in lesser amount in type II pneumocytes, type I pneumocytes, alveolar macrophages and bronchial epithelial cells, respectively. ISH has potential applications as a diagnostic test for the detection and differentiation of TGEV and PRCV in tissues and in studies to gain a better understanding of the mechanism of pathogenesis of enteric and respiratory coronavirus infections.

Keywords

Single stranded RNA probe, In situ hybridization, Transmissible gastroenteritis virus (TGEV), Porcine respiratory coronavirus (PRCV), Coronavirus