Using <i>Bacillus subtilis</i> as an oral vaccine carrier against <i>Streptococcus suis</i>

Abstract

Due to the progressive growth of the bacteria caused by the widespread use of antibiotics, treatment of streptococcosis is becoming increasingly difficult. Reliable vaccination against Streptococcus suis is necessary. Modern molecular diagnostic and genetic engineering capabilities create prospects for direct cloning of the protective epitopes of the Lmb gene of the local S. suis strain into the proposed delivery system of the pig immune system antigen. Among oral vaccine carriers, Bacillus subtilis is recognized as a relatively environmentally friendly carrier with an efficient protein secretion system and adaptive metabolism capable of spore production under relatively harsh conditions. This spore property can be used to increase the stability and reusability of vaccines. The possibility of using the protective Lmb epitopes of S. suis in B. subtilis as a carrier of an oral recombinant vaccine against Streptococcus suis was studied. The nucleotide sequences of S. suis were obtained from the GenBank database after a preliminary analysis of literature data on the known protective antigens of S. suis of various serotypes. Nucleotide sequence analysis was performed using Unipro UGENE v. 43.0. The Immune Epitope Database (IEDB) was used to search for T (CTL and Th) and B dependent epitopes of the Lmb gene. A computer-designed vaccine in which localization of CTL, B, and Th epitopes is predicted is described. The results of cloning the sequence of the antigenically active epitope of the S. suis Lmb protein in B. subtilis for subsequent oral administration and study of changes in immunological reactions and adverse reactions in animals are described. The possibility to clone the epitopes of recombinant S. suis Lmb protein into the pBE-S polylinker vector was revealed. In the long term, it seems possible to create a new inexpensive and easy-to-use vaccine against S. suis that does not require injection.