Effect of the size of polymer particles bearing protein antigen on the in vivo T-cellular immune response

In this work, we studied the effect of size of polymeric particles based on poly(D,L-lactic acid) bearing on the surface the fusion protein of human beta2-microglobulin with green fluorescent protein (β2M-sfGFP) on the levels of antigen-specific T-helper and cytotoxic T-lymphocytes.Microparticles with a diameter of about 1400 nm (MPs) and nanoparticles with a diameter of about 100 nm (NPs) were used as carriers for model protein.To evaluate the effect of different particle sizes on the immunogenicity of the model protein, two groups of mice were immunized so that the amount of β2M-sfGFP was equal.The identification of the antigen-specific interferon-producing T cells was carried out by the method of intracellular cytokine staining.For further analysis of T-lymphocyte populations, the method of flow cytofluorimetry was used.The number of antigen-specific CD4+ IFNγ-producing memory T cells (T-helpers) was not significantly different in the case of immunization with complex antigen MPs-β2M-sfGFP compared with the group immunized with antigen immobilized on the nanoparticles (NPs-β2M-sfGFP).However, the number of antigen-specific CD8+ T cells producing IFNγ was significantly higher (p = 0.031) in the case of immunization with complex antigen based on MPs compared to the group treated with the complex antigen based on NPs.