Fig 1: MSR vaccine generates potent humoral and cellular immune responses against a model antigen, OVA(a,b) ELISA analysis of sera OVA-specific IgG2a (a) or IgG1 (b) after immunization with bolus OVA, soluble components of the vaccine (bolus vaccine), MSRs loaded with OVA, or MSR vaccine, respectively (n=5). (c,d) ELISA analysis of sera OVA-specific (c) IgG2a and (d) IgG1 after immunization with bolus OVA, bolus vaccine formulation (GM-CSF, CpG, OVA), Imject Alum with OVA, MSR with OVA, and the MSR vaccine formulation on day 0, and boosted with the same formulations for each condition on day 30 (n=5). In (a–d), comparisons were made between vaccine and bolus formulation groups. (e,f) Flow cytometric analysis of proliferation of OVA-specific CD4+ T cells (gated on Thy1.2+ CD3+ T cells) (e) and CD4+ CXCR5+ T follicular helper (TFH) cells (gated on Thy1.2+ CD3+ T cells) (f) in naïve mice, or mice at day 3 post immunization with MSR loaded with non-specific antigen (MSR + Lysozyme), MSR loaded with OVA (MSR + OVA), or complete MSR vaccine (Vaccine) (n=4). (g,h) Number of tetramer+ CD8+ T cells (g) and IFN-γ+ CD8+ T cells (h) in spleen 7 days after vaccination with blank MSR (Blank) or complete MSR vaccine (Vaccine) (n=4). (i) Flow cytometric analysis of proliferation of OVA-specific CD8+ T cells in the draining lymph node (dLN; left) and spleen (right) of naïve mice, and mice at day 3 post immunization with complete MSR vaccine (Vaccine). (j,k) Prophylactic cancer vaccine study using injectable MSRs. (j) EG.7-OVA tumor volume and (k) survival rate after subcutaneous injection of various vaccine formulations 10 days before tumor inoculation (n=10). In (j), the tumor volumes were compared on day 21, 23 and 25, following the onset of tumor growth in the vaccine group. Biological replicates were used and studies were repeated at least 2 times in the lab. Values represent mean and S.D. with exception of Fig. 5j, which is expressed as mean ± SEM. *, **, and *** represents p<0.05, p<0.01, and p<0.001, respectively.