Abstract: The invention relates to a biologically pure strain of L. plantarum, L. plantarum, OM. The L. plantarum, OM strain has proteolytic, anti-viral, anti-retroviral, anti-bacterial, anti-microbial, and anti-tumoral characteristics and uses. Thus, the invention relates to agents having proteolytic, anti-viral, anti-retroviral, anti-bacterial, anti-microbial, and anti-tumoral agents, having the respective capabilities. With respect to its anti-viral capability, the provided strain includes the capacity to screen a pharmaceutical agent to determine whether the pharmaceutical agent has any anti-retrovirus activity. The invention also relates to a nutritional supplement having proteolytic activity and utilizing the L. plantarum, OM ATCC 55981 strain.