Background and study aim: Trichinellosis is a severe food-borne parasitic zoonosis. The protective immunity against infection from crude larval antigens (CLA) was performed effectively which suggests that the whole larvae would be possible vaccine candidates. Bone marrow mesenchymal stem cells (BM MSCs) induce immunomodulatory impacts through affection of T-cell proliferation and cytokine production.
Methods: Ninety healthy mice were divided into five main groups, 10 mice each, 30 mice were for attaining BM MSCs and 10 mice for CLA preparation. Group 1 & 2 as control, Group 3: immunized with CLA then infected, Group 4: immunized with MSCs then infected. Group 5 immunized with CLA and MSCs then infected.  Mice were challenged by orally infective dose with 500 Trichinella spiralis (T. spiralis) larvae.
Results: Showed that significant reduction in the number of T. spiralis larvae was in group 5 (received CLA + MSCs) followed by group 3 (received CLA only) then group 4 (received MSCs only) with percentage reductions of 85.4 %, 82 % and 68.9 %, respectively. G2 (infected only) showed absence of CD8+ infiltration. G3 showed moderate density of CD8+ infiltration, G4 and G5 showed high density CD8+ infiltration. However, muscle sections from G2 showed high density of tumor necrosis factor α (TNFα) infiltration; G3 showed moderate density of TNFα infiltration; G4 showed very low density of TNFα infiltration and G5 showed complete absence of TNFα infiltration.
Conclusion: We concluded that immunization by CLA combined with BM MSCs as adjuvant generated T-helper type 2 (Th2)-mediated responses with increased CD8+ cell infiltration and decreased TNF-α required for immunity against trichinellosis with a 85.4% reduction in muscle larvae compared with the control group.