Identification of monoclonal antibody reagents for use in the study of the immune response to infectious agents in camel and water buffalo

Progress in elucidating the mechanisms regulating the immune response to infectious agents and derived vaccines in domestic species, especially in camels and water buffalo, has been impeded by the lack of monoclonal antibody (mAb) reagents needed to study the immune response in the species of interest. As a first step to address this problem, we conducted a study to determine how many existing mAbs developed against leukocyte differentiation molecules (LDM) in various species recognise conserved epitopes on orthologous (identical) molecules in two or more species of Artiodactyla. Analysis of 490 monoclonal antibodies raised against LDM in cattle, goat, sheep, llama, pig, dog, and human revealed that many epitopes have been conserved on orthologous molecules in the course of evolution in closely related species in the suborder Ruminantia such as in cattle, bison, and water buffalo, and fewer on more distantly related species such as goat and sheep. Only a few of the epitopes conserved in Ruminantia were conserved in the suborders Suiformes (pigs) and Tylopoda (llamas and camels). The highest level of conservation in all suborders was found with major histocompatibility complex (MHC) class I (MHC I) and class II (MHC II) molecules. These findings show the potential as well as the limitations of screening existing mAbs for research in less use studied species. Importantly, the findings also provide further insight into the composition of the immune system in Artiodactyla and factors to be considered when studying the immune response to infectious agents and vaccines in the different suborders of Artiodactyla.