Monoclonal antibodies to Quebec strain (Q17) of bovine rotavirus

Detection of porcine respiratory coronavirus and transmissible gastroenteritis virus by an enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay (ELISA) for the detection of transmissible gastroenteritis virus (TGEV) and porcine respiratory coronavirus (PRCV) was developed. A bovine TGEV-specific polyclonal antibody was purified by affinity chromatography with the TRIO Bioprocessing System and was used as the capture antibody, at a concentration of 1.5 micrograms/well. The F5.39 monoclonal antibody was obtained by the fusion of spleen lymphocytes from TGEV immunized mice with NS-1 myeloma cells. This mAb was used as a second antibody for the ELISA. The ELISA detected 40 ng of TGEV and 407 ng of PRCV. To study the ability of ELISA to detect TGEV in field cases, 53 intestinal samples were taken from pigs exhibiting clinical signs of transmissible gastroenteritis. All the positive samples detected by the ELISA were confirmed as positive by immunofluorescence or cell culture immunofluorescence. To study the ability of this ELISA to detect PRCV in nasal swabs and lung samples, 20 seven-day-old piglets were inoculated with a Quebec strain of PRCV. The ELISA was able to detect PRCV in both kinds of samples.

Bovine rotavirus type detection by neutralizing monoclonal antibodies

A series of monoclonal antibodies were developed against bovine rotavirus Q17. Among the five high affinity antibodies characterized, two (RQ 31 and RQ 4) were able to neutralize type G 6 viruses and may be specific for PB 1 type virus. Seventy seven feces from diarrheic calves were tested by "double sandwich" ELISA using four monoclonal and one polyclonal anti-rotavirus antibodies. The combination of mono- and polyclonal antibodies thus appears to be a more efficient strategy for detection and typing of bovine rotaviruses.

Monoclonal anti-idiotype induces antibodies against bovine Q17 rotavirus

This study describes, for the first time, the production and use of an "internal-image" anti-idiotypic monoclonal antibody (MAb) to elicit a rotavirus-specific antibody response. An immunoglobulin G2a MAb, designated RQ31 (MAb1), specific for the outer capsid protein VP4 of bovine Q17 rotavirus and capable of neutralizing viral infection in vitro was used to generate an anti-idiotypic MAb (MAb2). This MAb2, designated RQA2, was selected by enzyme-linked immunosorbent assay (ELISA) using F(ab')2 fragments of RQ31. RQA2 (MAb2) inhibited the binding of RQ31 (MAb1) to the virus but had no effect on the binding of other rotavirus-specific MAbs. The MAb2 also inhibited virus neutralization mediated by MAb1 in a dose-dependent fashion. Naive guinea pigs immunized with the MAb2 produced anti-anti-idiotypic antibodies (Ab3) that reacted with bovine Q17 rotavirus in an ELISA and neutralized rotavirus infection in vitro. The Ab3 response was characterized as MAb1-like because the Ab3 recognizes only the Q17 and neonatal calf diarrhea virus rotavirus strains in ELISA, as did RQ31 (MAb1). The Ab3 response also possessed two other characteristics of RQ31: the abilities to bind the 1.36 (double-capsid) but not the 1.38 (single-capsid) purified rotavirus fraction in ELISA and to immunoprecipitate the VP4 rotavirus protein.