ABSTRACT
Cell therapy with bone marrow-derived mononuclear cells is an alternative to therapy with mesenchymal stem cell cultures. The aim of the present research was the comparison of the yield of bone marrow-derived mononuclear cells harvested from dogs with two different anticoagulants. Bone marrow was harvested from the iliac crest of five healthy dogs aged between 15 and 30 months, and the effect of two anticoagulant solutions, CPDA-1 (citrate phosphate dextrose adenine-1) and heparin, on the isolation of mononuclear cells was compared. Mononuclear cells were isolated in a density gradient and stained for CD9 and CD44 for characterization by flow cytometry. Means were compared using Student's paired t-test. Samples harvested with CPDA-1 yielded an average of 5.16x106 (±1.76x106) to 20.20x106 (±1.55x106) mononuclear cells/mL, whereas the yield of samples harvested with heparin varied between 4.56x106(±0.69x106) and 24.30x106 (±2.12x106) mononuclear cells mL-1. By flow cytometry, mean percentage of double-stained cells varied from 1.96% (±0.64%) to 5.01% (±0.73%) for CPDA-1 and from 2.23% (±0.70%) to 7.27% (±0.97%) for heparin. No significant statistical differences were observed on yield or CD9 and CD44 expression. Further studies are recommended to assess efficacy of CPDA on mononuclear cell isolation.
A terapia com células mononucleares de medula óssea é uma alternativa ao cultivo de células-tronco mesenquimais. O objetivo deste trabalho foi comparar o rendimento de células mononucleares derivadas da medula óssea de cães, colhidas com dois anticoagulantes diferentes. Foram coletadas medulas ósseas de cinco cães hígidos, com idades variando entre 15 e 30 meses, por punção na crista ilíaca. Foi comparado o efeito da solução anticoagulante no isolamento das células mononucleares, utilizando-se CPDA-1 (citrato, fosfato, dextrose, adenina) ou heparina como soluções anticoagulantes. As células mononucleares foram isoladas em gradiente de densidade e caracterizadas fenotipicamente em citometria de fluxo. Os resultados foram submetidos ao Teste t pareado para comparação de médias. Nas amostras coletadas com CPDA-1, o rendimento médio variou entre 5,16 x 106 (±1,76x106) a 20,20x106 (±1,55x106) células mononucleares mL-1, enquanto que, nas amostras coletadas com heparina, o rendimento variou entre 4,56x106 (±0,69x106) a 24,30x106(±2,12x106) células mononucleares/mL. Na citometria de fluxo, a média de células duplo-marcadas variou de 1,96% (±0,64%) a 5,01% (±0,73%) para CPDA-1 e de 2,23% (±0,70%) a 7,27% (±0,97%) para heparina. Não foram observadas diferenças estatísticas no rendimento ou na expressão de CD9 e CD44. Recomendam-se estudos adicionais para avaliar melhor a eficácia do CPDA no isolamento de células mononucleares.
ABSTRACT
Avian pathogenic Escherichia coli is a current problem in the poultry industry, causing mortality and economic losses. This paper evaluates the dynamics in immune response after the use of spray vaccination against E. coli and, thereby, seeks to understand how the vaccine can provide protection. During the early stages of response to vaccination the presence of antigen-presenting cells is predominant, but these diminish within the first 7 days after vaccination. The immune correlate of protection of vaccination using the E. coli vaccine Poulvac E. coli (aroA-deficient mutant strain) probably does not depend on the production of circulating antibodies (as assessed through the presence of B lymphocytes) and is linked to the presence of CD4+TCRVbeta1+. These cells act on mucosa tissue stimulating the production of immunoglobulin A. Vaccination stimulated a high state of immunocompetence, as assessed by measurement of several cellular subsets. This state of "immune alertness," however, may be associated with reduced weight gain. The high presence of naive and memory CD8 cells in the vaccinated group at 14 and 21 days postvaccination may indicate greater ability in the future to prevent tissue invasion by E. coli, based on the possibility that these cells will proliferate rapidly to a new stimulus. The simultaneous use of vaccine with the antibiotic ceftiofur sodium interferes with the immune response obtained through vaccination. In combination, the data obtained in this study indicate that the immune response produced by a spray vaccine against E. coli is mainly a cellular response, especially relevant to the sites in contact with the pathogen. It is suggested that there is a strong cell migration to the mucous membranes, where macrophages act first and then lymphocytes take part to protect the host. It is believed that recruited lymphocytes will act in the production of secreted IgA, which probably plays a greater role in the defense when compared with circulating immunoglobulins. The assessment of cellular dynamics by flow cytometry made it possible to elucidate the operation mechanism of the live E. coli vaccine.
