Canine Parvovirus Isolates of India and the Relevance of Canine Parvovirus Type-2 Vaccines

A study was conducted to characterise the field isolates of canine parvovirus (CPV) and an in vitro cross neutralisation assay was performed against the vaccinated dog sera. Out of 45 faecal samples processed for virus isolation, 27 samples showed cytopathic effect (CPE) at first passage, which were confirmed positive by CPV variant types specific PCR. The CPV type 2 was not detected in any of the clinical samples. Of these 27 positive samples only 23 samples showed CPE and were further confirmed as CPV by haemagglutination inhibition test, ELISA and immuno-chromatographic strip test. Antigenic typing performed using a panel of monoclonal antibodies revealed that four of the 23 isolates were CPV 2b type and the remaining 19 isolates were typed as CPV 2a. The antigenic typing results obtained using the monoclonal antibodies corroborated the sequencing results reported by our group earlier. The cross neutralization study with polyclonal sera revealed that the sera of original antigenic type CPV 2 can neutralize the antigenic variants 2a and 2b effectively. Thus we conclude that the vaccines containing CPV type 2 virus can be used to immunise the dogs against the prevalent CPV 2a and CPV 2b infection. A live virus challenge study in dogs may further confirm this observation

Immuno-affinity Purification of Insect Cell Expressed Rabies Virus Glycoprotein using a Conformational Specific Monoclonal Antibody

.Rabies is a disease of nervous system and causes progressive encephalitis with fatal outcome. The conformation-dependent epitopes on the glycoprotein (G) of rabies virus (RV) is responsible for the induction of virus neutralizing antibodies which is ultimately required to get complete protection from viral challenge. Therefore, a suitable chromatography technique is necessary to purify the tag free recombinant rabies virus glycoprotein (rRVG) without altering its immunogenic epitopes. The present study was undertaken to purify the rRVG using a conformational specific anti-rabies virus glycoprotein (RVG) mAb, M5B4, which binds to the natively folded G. The mAb had shown a significant kinetic interaction with RVG. The mAb immobilized onto the NHS-activated Sepharose 4 fast flow™ was used for the purification of rRVG by immuno-affinity chromatography (IAC). The bound rRVG was eluted in IAC using 0.1M glycine with pH 2.5 and the identity of the purified protein was confirmed by MALDI-TOF. The IAC purified rRVG induced neutralizing antibody response and 83% of the immunized mice were protected against intra-cerebral rabies virus challenge. The results indicate that the mAb based IAC method can be an effective purification technique for tag free rRVG with significant level of purity, without compromising the protein’s immunogenic potential