Comparison of indirect based ELISA by employing purified LLO and its synthetic peptides and cultural method for diagnosis of ovine listeriosis

Seropositivity of Field Veterinarians for Listeric Infection by Indirect ELISAs Employing Recombinant and Wild-Type Listeriolysin O

“…LLO is antigenically related to a number of cytolysins, including SLO from Streptococcus pyogenes, pneumolysin from Streptococcus pneumoniae and perfringolysin from Clostridium perfringens. Adsorption of the test sera with SLO has been found to cause 3-fold reduction in ALLO titers on account of eliminating the marked cross-reactivity in human clinical case of encephalitis (Berche et al, 1990) and abortions (Kaur et al, 2006) as well as animal listeriosis cases in cattle (Shivaramu, 2008) and sheep (Shoukat et al, 2013a).…”

“…On the other hand, serological tests have the advantage of large number of mass screening, and are economical, easy-to-perform and interpret. Ideally, such test must have sufficient sensitivity, specificity to detect the humoral response directed against the immunogenic component of the agent, preferably those linked to its virulence (Shoukat et al, 2013a). Many serodiagnostic assays have been developed for screening animal and human listeriosis cases either by employing the somatic (O), flagellar (H), cold-extracted or sonicated listerial antigens or outer membrane protein (OMP) of Listeria spp.…”

“…However, the cross-reactivity of antibodies against LLO (ALLO) with those produced against streptolysin O (SLO), a haemolysin produced by Streptococcus spp. remains a major limitation of this assay, which calls for adsorption of test sera with SLO prior to its testing by this assay (Berche et al, 1990;Kaur et al, 2006;Shivaramu, 2008;Shoukat et al, 2013a). Therefore, recombinant forms of LLO (rLLO) have been explored as an alternative to wild type LLO (wLLO) as a diagnostic antigen in Western blot assays (OIE, 2008).…”

Comparative efficacy of Internalin C-based peptide and listeriolysin O-based enzyme linked immunosorbent assays for serodiagnosis of listeric infection in goats

“…since the discovery of the bacterium with the aim of identifying the bacteria quickly, and with a greater degree of sensitivity (Jadhav et al, 2012;Shoukat et al, 2013). The humoral immune response is normally detected during listerial infection even in the absence of clinical symptoms.…”

“…produced by virulencelinked family of genes (Boerlin et al,2003); Act A protein associated with cell-to-cell spread of the agent (Ellin Doyle, 2001), two phospholipases C namely the PI-PLC encoded by plcA gene and the PC-PLC encoded by plcB (Chaudhari et al, 2004a,b); and the autolysin p60 protein (Hess et al, 1996). Out of the mentioned markers, LLO a 58-kDa secreted protein is one of the most important virulence factor produced by L. monocytogenes which can be detected soon after clinical onset of listeriosis and antibodies persist for at least several months (Berche et al, 1990;Shoukat et al, 2013). LLO based ELISA had been used (Low and Donachie, 1991;Low et al, 1992;Boerlin, 2003) however, LLO cross reacts with streptolysin, perfrinolysisn, suilysin and hence need prior adsorption at least with streptolysin O (SLO) before performing LLO-based ELISA (Berche et al, 1990).…”