NASAL VACCINE AGAINST STREPTOCOCCUS PNEUMONIAE: IMMUNE RESPONSE IN NASOPHARYNGEAL-ASSOCIATED LYMPHOID TISSUE (NALT)

VINTIÑI ELISA; MARCELA MEDINA

Rosario, Santa Fe

Congreso; II Reunión Internacional de Ciencias Farmacéuticas; 2012

Colegio de Farmacéuticos de Santa Fe- Colegio de Farmacéuticos de Córdoba

NASAL VACCINE AGAINST STREPTOCOCCUS PNEUMONIAE: IMMUNE RESPONSE IN NASOPHARYNGEAL-ASSOCIATED LYMPHOID TISSUE (NALT) Vintiñi EO1,2, Medina MS*2,3 1- Fac. Agronomía y Zootecnia-UNT. Tucumán.Argentina. 2- CERELA. Tucumán. Argentina. 3- Fac. de Bioquímica, Química y Farmacia-UNT. Tucumán. Argentina. INTRODUCTION Pneumococcal infections are one the most common diseases around the world (1). At present, available pneumococcal vaccines have failed to eradicate infections caused by Streptococcus pneumoniae. Some serotype independent pneumococcal proteins are considered as candidates for the design of new vaccines. Nasal vaccines represent an option for mucosal immunization against pneumococci. Selection of appropriate adjuvants is crucial for mucosal vaccines and lactic acid bacteria (LAB) with immunostimulant properties are promissory candidates (2). Objective To evaluate the adaptative immune response induced in nasopharynx after nasal immunization with a pneumococcal antigen (pneumococcal protective protein A: PppA) associated to heat-killed Lactobacillus casei 431 (LcM). Material and Methods Young mice (3 weeks) were nasally immunized with 30 ul of PppA (10 ug) + LcM (109 CFU) as the mucosal adjuvant. The protocol of immunization was comprised of 3 successive administrations that included two consecutive days each time with a 14-day interval beetween them (days 0-1, 14-15 and 28-29). Groups that received LcM, PppA and PBS were used as controls. Samples of nasal lavages (NL) were collected on days 0, 14, 28 and 42. On day 42, nasopharyngeal-associated lymphoid tissues (NALT) were collected to flow cytometry studies, and also head of mice were obtained for histological analysis. Assays: 1) Specific anti-PppA IgA e IgG antibodies were determined by ELISA, 2) CD3+, CD4+, CD8+ and IgA+ cells in NALT determined by flow cytometry, 3) IL-2, INF-gamma (Th1 cytokines), IL-4, IL-10 (Th2 cytokines) and IL-17 (Th17) were evaluated by ELISA 4) Histological observation of NALT was performed by H&E staining. Results In NL, PppA+LcM induced high levels of IgA and IgG anti-PppA compared with PppA. LcM and PBS experimental groups induced no specific anti-PppA antibodies. In control group, most T CD3+ cells of NALT are CD4+ cells, while that the percentage of CD8+ cells are lower. Fourteen days post 3rd immunization, experimental groups that received LcM and LcM+PppA increased significantly the total of CD3+ T cells, CD4+ cells and CD8+ cells, compared with PBS and PppA group. In addition, IgA+ cells were increased in NALT when mice were immunized by LcM and PppA+LcM. These last groups also increased the Th1 cytokines (IL-2 and INF-gamma), Th2 cytokines (IL-4, IL-10) and Th17 cytokines (IL-17), compared with other experimental groups. When mice were immunized with PppA+LcM, histological analysis of nasopharynx by H&E staining showed a cellularity higher than control group. Conclusions Nasal immunization with PppA+LcM was able to stimulate cellular and humoral immune response in nasopharynx. Thus, specific anti-PppA IgA and IgG antibodies were induced, and IgA+ cells were increased in NALT. In addition, PppA+LcM induced activation of T cells with production of cytokines Th1, Th2 and Th17. PppA+LcM could be of great value in the development of nasal vaccine to prevent pneumococcal infections. ACKNOWLEDGMENTS This work was supported by PICT2010 N°828, PIP 632 and CIUNT 403-3 REFERENCES 1. Dockrell DH, Whyte MK, Mitchell TJ (2012) Pneumococcal pneumonia: mechanisms of infection and resolution. Chest 142: 482-491. 2. Wells JM, Mercenier A (2008) Mucosal delivery of therapeutic and prophylactic molecules using lactic acid bacteria. Nat Rev Microbiol 6: 349-362 Vintiñi EO, Tel: 0381-1557569213, *e-mail: marcemedina74@yahoo.com.ar