Utility of recombinant LipL41 based IgM and IgG ELISA in diagnosis of canine leptospirosis in an endemic area - a study from Kerala, India.

A study was undertaken to evaluate the relevance of detecting IgM and IgG antibodies in diagnosis of canine leptospirosis in Kerala, a southern state of India, which is endemic for the disease. A total of 205 blood (35 from healthy vaccinated, 30 from healthy unvaccinated and 140 from diseased dogs) and 151 urine samples (11 from healthy vaccinated and 140 from diseased dogs) were collected from three districts of Kerala, Thrissur, Palakkad and Kozhikode with high incidence of leptospirosis. Recombinant LipL41 protein was used as antigen and IgG and IgM based ELISAs were standardized. The results were compared with the gold standard test, microscopic agglutination test (MAT). The MAT positive samples (146 samples) were divided into those having titre >1:800 and those between 1:100 and 1:400 in view that the former constituted the acute cases. It was found that IgM ELISA was more specific and sensitive in detecting acute cases (MAT >1:800) whereas IgG ELISA was less specific. In case of seroprevalence studies (MAT titre 1:100 to 1: 400), IgG ELISA was found to be more sensitive and specific than IgM ELISA. Receiver operating characteristic curves when plotted, revealed the accuracy of IgM ELISA in acute leptospirosis. Many samples were positive for both IgG and IgM antibodies. Polymerase Chain Reaction (PCR) targeting lipl41 gene was standardized and urine and blood samples from the same dogs were tested. PCR was found to be the specific test for the early detection of leptospires in blood even before seroconversion. However, PCR analysis of the urine samples was found to be insensitive. Hence, it can be concluded that the diagnostic strategies should be modified, and a combination of serological and molecular tests is recommended in endemic areas rather than simple detection of IgM or IgG antibodies, for the early detection of acute clinical cases of leptospirosis.

Utility of recombinant LipL41 based IgM and IgG ELISA in diagnosis of canine leptospirosis in an endemic area – a study from Kerala, India

@#A study was undertaken to evaluate the relevance of detecting IgM and IgG antibodies in diagnosis of canine leptospirosis in Kerala, a southern state of India, which is endemic for the disease. A total of 205 blood (35 from healthy vaccinated, 30 from healthy unvaccinated and 140 from diseased dogs) and 151 urine samples (11 from healthy vaccinated and 140 from diseased dogs) were collected from three districts of Kerala, Thrissur, Palakkad and Kozhikode with high incidence of leptospirosis. Recombinant LipL41 protein was used as antigen and IgG and IgM based ELISAs were standardized. The results were compared with the gold standard test, microscopic agglutination test (MAT). The MAT positive samples (146 samples) were divided into those having titre >1:800 and those between 1:100 and 1:400 in view that the former constituted the acute cases. It was found that IgM ELISA was more specific and sensitive in detecting acute cases (MAT >1:800) whereas IgG ELISA was less specific. In case of seroprevalence studies (MAT titre 1:100 to 1: 400), IgG ELISA was found to be more sensitive and specific than IgM ELISA. Receiver operating characteristic curves when plotted, revealed the accuracy of IgM ELISA in acute leptospirosis. Many samples were positive for both IgG and IgM antibodies. Polymerase Chain Reaction (PCR) targeting lipl41 gene was standardized and urine and blood samples from the same dogs were tested. PCR was found to be the specific test for the early detection of leptospires in blood even before seroconversion. However, PCR analysis of the urine samples was found to be insensitive. Hence, it can be concluded that the diagnostic strategies should be modified, and a combination of serological and molecular tests is recommended in endemic areas rather than simple detection of IgM or IgG antibodies, for the early detection of acute clinical cases of leptospirosis.

Generation and characterization of neutralizing monoclonal antibodies against baculo-expressed HPV 16 VLPs.

Human papillomavirus (HPV) is the well-known second most cause of cervical cancer in women worldwide. According to the WHO survey, 70% of the total cervical cancers are associated with types HPV 16 and 18. Presently used prophylactic vaccine for HPV contains mainly capsid protein of L1 virus like particles (VLPs). Correct folding of VLPs and display of neutralizing epitopes are the major constraint for VLP-based vaccines. Further, monoclonal antibodies (mAbs) play a vital role in developing therapeutics and diagnostics. mAbs are also useful for the demonstration of VLP conformation, virus typing and product process assessment as well. In the present study, we have explored the usefulness of mAbs generated against sf-9 expressed HPV 16 VLPs demonstrated as type-specific and conformational dependent against HPV 16 VLPs by ELISA. High affinity and high pseudovirion neutralization titer of mAbs indicated their potential for the development of prophylactic vaccines for HPV. Also, the type-specific and conformational reactivity of the mAbs to HPV 16 VLPs in sf-9 cells by immunofluorescence assay proved their diagnostic potential.