Immunological characterization of the Marin County strain of astrovirus

Abstract

Marin County virus (MCV) was isolated from a stool suspension and serially propagated in human embryonic kidney cell cultures. MCV particles in stool and cell-propagated virus stocks showed reactivity by immune electron microscopy (IEM) with rabbit antiserum to astrovirus type 5. MCV antigen was also detected in two MCV stool samples by enzyme immunoassay (EIA) with an astrovirus group-specific monoclonal antibody. Acute and convalescent sera from 3 of 3 MCV-infected patients showed seroconversion to cell-propagated MCV by EIA. Immunofluorescence of MCV propagated in cell culture showed positive reactivity with an astrovirus group specific monoclonal antibody and astrovirus type 5 antiserum, with some cross-reactivity with astrovirus type 1. Similar results were obtained with the prototype strain of astrovirus type 5. However, in plaque-reduction assays, both the prototype astrovirus type 5 and MCV were neutralized by type 5 antiserum only. We conclude that MCV can be serially propagated by techniques used for previously described astroviruses and is serotypically an astrovirus type 5.

Seroprevalence of astrovirus types 1 and 6 in London, determined using recombinant virus antigen

“…A fourfold response to HAst-1, 1/20 (acute phase)-1/80 (convalescent phase) was demonstrated by immunofluorescence in a volunteer challenged with HAst-5. Similar responses were previously demonstrated by IEM and RIA [6,12].…”

“…Pre-and post-challenge sera were obtained from an adult volunteer (DA) infected with a faecal extract derived from material obtained from the original outbreak which occurred in California in 1978 [13]. Subsequent studies identified the causative agent as astrovirus type 5 [6,10,15]. All sera had been stored at -20 C.…”

“…However, until the production of a group specific monoclonal antibody in 1988 [2] and the subsequent development of an enzyme immunoassay (EIA) [3] diagnosis depended on electronmicroscopy (EM). The application of EIA has provided increasing evidence that astroviruses may be a more common cause of diarrhoea than previously supposed [4,5] but a limited supply of reference typing antisera has meant that its application has been confined to one or two research laboratories in the USA and UK [6][7][8]. Data on the seroprevalence of astroviruses is even more sparse, being limited to two surveys; an immunofluorescence study on the prevalence of antibodies to human astrovirus type 1 (HAst-1) using 87 sera from children in the Oxford area of England [9] and human * Author for correspondence.…”

Typing of human astroviruses from clinical isolates by enzyme immunoassay and nucleotide sequencing

“…Astroviruses are currently classified into seven antigenic types, HAstV-1 to HAstV-7, on the basis of immune EM and immunofluorescence techniques (18)(19)(20) using polyclonal and monoclonal antibodies (10) to cell culture-adapted virus. Epidemiologic studies using EM (2,16,21,22,30,40) and the more recently developed enzyme immunoassays (EIAs) (3,9,11,12,17,23,28,29,33) have demonstrated the worldwide distribution of astroviruses.…”

Complete genome sequence of an astrovirus identified in a domestic rabbit (Oryctolagus cuniculus) with gastroenteritis

“…Indeed, samples from three of the other four sick rabbit from the same outbreak tested negative for the virus (Table 1). Nevertheless, astroviruses cause gastroenteritis in other mammals, and it is possible that this virus caused or exacerbated the illness in a subset of the animals [13,24,25,28,29,47]. The coccidian parasites and bacteria evident in the samples may have also contributed to the enteritis and from this data alone, it is impossible to ascertain whether this astrovirus is capable of causing disease.…”