Impact of mouse pregnancy on thymic T lymphocyte subsets.

It has been reported that fetal lymphoid progenitor cells are acquired during gestation and are able to develop in the maternal mouse thymus into functional T cells. Moreover, previous pregnancies increase the number of fetal cells in the mother. In the present study, we investigated whether mouse pregnancy induces changes in T lymphocyte subsets in the maternal thymus. We determined the T lymphocyte subsets in two allogeneic cross-breedings, namely CBA/J×BALB/c (normal) and CBA/J×DBA/2 (abortion prone), and investigated the effects of the age and parity of the female, as well as pregnancy outcome, on thymocyte populations. In addition, hormonal effects were evaluated in a syngeneic combination (CBA/J×CBA/J). We found that during pregnancy both hormonal and allogeneic stimuli induced a reduction in the CD4(+)CD8(+) subset with an increase in the CD4(+)CD8(-) population. Only young females of the normal combination exhibited an increase in the CD4(-)CD8(+) population. All young mice showed an increase in CD4(+)CD25(+)FoxP3(+) T cells. Interestingly, the γδT thymus pool was increased in all females of the normal allogeneic pregnancy only, suggesting the participation of this pool in the observed beneficial effect of multiparity in this cross-breeding. Our results demonstrate that allogeneic pregnancies induce important variations in maternal thymocyte subpopulations depending on the age of the female and the male component of the cross-breeding.

Trichinella spiralis infection rapidly induces lung inflammatory response: the lung as the site of helminthocytotoxic activity.

In the present work, we studied the kinetics of the appearance of different immunological parameters in the lungs during the intestinal phase of infection with Trichinella spiralis. We also evaluated the lung's role in the retention and death of this helminth in its migratory stage. To study these parameters, we used lung extracts, lung cell suspensions and rat lung tissue sections. During the intestinal phase of infection (days 0-13 post-infection, p.i.), an inflammatory response is elicited in the lungs, which reflects humoral, cellular and functional changes. These changes included an increased number of mast cells and eosinophils and the local production of IL-4, IL-5, IL-10, TNFα, IFNγ, IL-13, CCL11 and CCL28. We found hyperplasia of the bronchus-associated lymphoid tissue (BALT). Total and specific IgA, IgE, IgG1 and IgG2a were detected locally. The retention of the migratory larvae in the lung, together with the ex vivo cytotoxic capacity of the lung cells and antibodies present in the lung extracts, suggested that the lung was one of the immune defense organs against the pathogen's migration stage.

Multiparity increases trophoblast invasion and vascular endothelial growth factor expression at the maternal-fetal interface in mice.

To analyze immunomodulating effects related to parity status, we studied trophoblast invasion grade, placental expression and systemic concentration of VEGF and its receptor Flt-1 in normal fertile (CBA/JxBALB/c) mice and abortion-prone (CBA/JxDBA/2) H-2(d)xH-2(k) mice. BALB/c or DBA/2 mated CBA/J females were, respectively, divided into the following groups: primiparous young (3.0+/-0.5 months old); primiparous old (8.5+/-0.5 months old) and multiparous old (8.5+/-0.5 months old, with 4 pregnancies). Immunohistochemical analysis of term placentae from both multiparous groups revealed various layers of invasive trophoblast tissue, identified as cytokeratin+/vimentin- cells, in contrast to the single layer detected in the placentae of primiparous animals, indicating that multiparity increases trophoblast invasion regardless of the success of the pregnancy outcome. Invasive trophoblast tissue from primiparous CBA/JxDBA/2 placentae showed diminished VEGF expression in comparison with the normal fertile group, while both multiparous groups demonstrated high expression of VEGF in the invasive trophoblast tissue. Placental expression of Flt-1 was similar in all groups. However, the primiparous CBA/JxBALB/c group showed the highest plasma concentration of sFlt-1 at term, while both multiparous groups demonstrated low circulating levels. No differences in circulating VEGF levels were observed among the groups. These results demonstrate an increase in trophoblast invasion tissue and expression of VEGF in the maternal-fetal interface in multiparous mice compared to primiparous mice. Moreover, the placenta appears to be able to regulate the circulating levels of VEGF by releasing sFlt-1.

Early appearance of TNF-alpha and other cytokines in bronchus associated lymphoid tissues (BALT) from growing Wistar rats. what is the role of TNF-alpha?

Several different cytokines trigger the development of determined cell subsets in BALT of growing Wistar rats. Early appearance (4 days post partum) of gammadeltaT cells in BALT has been shown, as well as its role in up-regulating TNF-alpha production. In the present report, we studied in the BALT: (1) the profile of the cytokines, TNF-alpha, INF-alpha and IL-10 and (2) in TCR gammadelta+ cells, the existence of a colocalization with TNF-alpha as well as with INF-gamma. All the cytokines studied were observed at an early stage of BALT development by immunohistochemistry and in bronchoalveolar cells (BAL cells) by flow cytometry and western blot. (1) The principal cytokine found at 4 days of age in BALT cells was TNF-alpha that increases along BALT development. The same behavior was found for cells containing IL-10 and INF-gamma. (2) TCR gammadelta+ cells colocalize mainly with TNF-alpha as it has been shown by immunohistochemistry in BALT and by flow cytometry when we studied BAL. The early appearance of TNF-alpha concomitant with TCR gammadelta+ cell suggests an important role for this cytokine along BALT development. Moreover, mutual regulation between them exists taking part in the immune surveillance and repair of damaged epithelia.

Development of T lymphocytes in the nasal-associated lymphoid tissue (NALT) from growing Wistar rats.

The aim of the present report was to study the development of several T-lymphocyte subsets in the nasal-associated lymphoid tissue (NALT) of growing Wistar rats. CD5+ and CD4+ lymphocytes gradually increased with age. A predominance of CD8alpha+ over CD4+ T cells was found from 7 to 45 days but from 45 to 60 days of age T helper cells outnumbered the cytotoxic subpopulation. The majority of CD8+ T lymphocytes expressed the heterodimeric isoform. The most relevant findings by immunohistochemistry are: (1) the predominance of TCRgammadelta+ and CD8alpha+ cells at 7 days postpartum over all the other T-cell subpopulations; and (2) that TCRgammadelta+ outnumbered TCRalphabeta+ T cells from 7 to 45 days postpartum whereas alphabeta T cells predominated in 45- and 60-day-old rats. Besides, cytometric studies have shown that the percentages of TCRgammadelta+, CD8alpha+, as well as the population coexpressing both phenotypes (TCRgammadelta+CD8alpha+), were significantly higher in rats at 7 days postpartum when compared to 60 day-old rats. In the present study, the finding of a high number of gammadelta+ and CD8+ T cells early in NALT development may indicate the importance of these subpopulations in the protection of the nasal mucosa in suckling and weaning Wistar rats.

The Oral Administration of Lactic Acid Bacteria Increase the Mucosal Intestinal Immunity in Response to Enteropathogens.

The present studies were designed to investigate the effect of orally administered Lactobacillus casei , Lactobacillus acidophilus , Lactobacillus delbrueckii spp., bulgaricus , and Streptococcus salivarius ssp. thermophilus on local mucosal immunity in response to enteropathogens. Normal mice were protected against Salmonella typhimurium infection by previous feeding with L. casei and S. salivarius spp. thermophilus , while L. acidophilus and L. delbrueckii spp. bulgaricus were not effective. The protective effect of L. casei against S. typhimurium was associated mainly to IgA production in intestinal secretions. We observed significant differences in the intestinal fluid anti- Salmonella agglutinin titers between the Salmonella -challenged control group (without lactobacilli feeding) and mice pretreated with L. casei . The level of immunoglobulins from intestinal fluid of mice fed previously with lactic acid bacteria was measured by radial immunodiffusion assay showing in all cases an increase in the immunoglobulin concentrations. By Immunoelectrophoresis methods, we observed the presence of two lines of immunoprecipitation. When we used monospecific serum, we detected the presence of IgG and IgA. Elisa tests showed high levels of IgA to S. typhimurium in intestinal secretions of mice pretreated with L. casei , while L. acidophilus and L. delbrueckii spp. bulgaricus groups showed values at slightly higher levels than the controls. The levels of IgG to S. typhimurium were similar to controls in all cases. We did not observe antibodies against the pathogen in intestinal fluid from mice fed with S. salivarius spp. thermophilus . However, we detected anti- Streptococcus antibodies. These results show that only L. casei increases the IgA production secreted to the intestinal lumen, providing adequate defenses at mucosal surfaces, and suggest that this microorganism could be used as oral adjuvant especially to prevent enteric infections.

Immunohistochemical studies on the small intestine of immunodeficient rats

Se estudió la histoarquitectura de la mucosa intestinal en un modelo experimental de inmunodeficiencia utilizando ratas Wistar que al destete recibieron una dieta libre de protéinas (13-17 días) a las que posteriormente se les adminsitró, por vía oral, caseína al 20% durante 39 días (grupo A) y en controles que recibieron desde el destete dieta comercial (grupo B). En el estudio del intestino delgado no se observaron diferencias significativas en los siguientes parámetros: altura de la mucosa, altura de las vellosidades, relación cripta/vellosidad, número de células epiteliales y número decélulas caliciformes. Se observó diferencia en el número de células del corion: (p < 0.05). A partir de estos dados resultó de interés investigar el número de células plasmáticas IgA, IgM y IgE presentes en la lámina propia del intestino delgado. Los resultados indican disminución estadísticamente significativa en el número de células plasmáticas IgA (p < 0.002), IgM (p < 0.002) e IgE (p < 0.02) en las ratas que después de la deficiencia proteica recibieron caseína al 20% durante 40 días. El daño provocado en la diferenciación terminal de los precursores de células plasmáticas IgA, Por la deficiencia proteica, no se revieste con la administración de caseína al 20% durante 39 días. La deficiencia de IgA provocada por la carencia de proteínas no es compensada con un aumento del número de células plamáticas IgM o IgE

Immunohistochemical studies on the small intestine of immunodeficient rats

Se estudió la histoarquitectura de la mucosa intestinal en un modelo experimental de inmunodeficiencia utilizando ratas Wistar que al destete recibieron una dieta libre de protéinas (13-17 días) a las que posteriormente se les adminsitró, por vía oral, caseína al 20% durante 39 días (grupo A) y en controles que recibieron desde el destete dieta comercial (grupo B). En el estudio del intestino delgado no se observaron diferencias significativas en los siguientes parámetros: altura de la mucosa, altura de las vellosidades, relación cripta/vellosidad, número de células epiteliales y número decélulas caliciformes. Se observó diferencia en el número de células del corion: (p < 0.05). A partir de estos dados resultó de interés investigar el número de células plasmáticas IgA, IgM y IgE presentes en la lámina propia del intestino delgado. Los resultados indican disminución estadísticamente significativa en el número de células plasmáticas IgA (p < 0.002), IgM (p < 0.002) e IgE (p < 0.02) en las ratas que después de la deficiencia proteica recibieron caseína al 20% durante 40 días. El daño provocado en la diferenciación terminal de los precursores de células plasmáticas IgA, Por la deficiencia proteica, no se revieste con la administración de caseína al 20% durante 39 días. La deficiencia de IgA provocada por la carencia de proteínas no es compensada con un aumento del número de células plamáticas IgM o IgE (AU)

Sistema linfoide y deficiencia proteica: deferenciación en timo y placas de Peyer / Lymphoid system and protein deficiency: differentiation in thymus gland and Peyer's patches

En un modelo experimental de inmunodeficiencia provocada por déficit de proteínas, se demuestra: 1) en el timo, existencia de graves alteraciones en sus poblaciones celulares que se encuentran drmáticamente disminuídas: W3/13+ (pan- T), W3/25+ (CD4+) y OX8+ (DC8+), existiendo una población celular que contiene TdT como único marcador; 2) alteraciones en el ciclo celular de la IgA que permitieron demostrar in vivo la presencia de células pre-B en placas de Peyer con alteración marcada en las subpoblaciones T; 3) los mecanismos involucrados en la inmunidad mediada por células son dañados por el déficit de proteínas y continúan alterados después de que dicho déficit ha sido superado; 4) en el timo, la administración por via oral de una dieta de caseína al 20% restaura la población celular- T W3/13+ luego de 21 días, pero la subpoblación W3/25+ (CD4+) se encuentra muy disminuida; 5) al mismo tiempo se reinicia, en placas de Peyer, la diferenciación de los precursores de células plasmáticas de clase IgA, aunque se encuentra la diferenciación de los precursores de células plamáticas de clase IgA, aunque se encuentra alterado, tanto en ellas como en ganglio mesentérico, el número absoluto de células que expresan y contienen IgA, así como el de las células T maduras, especialmente la población CD4+; 6) el dearrollo de un mecanismo de tolerancia a dextrina que es antígeno-específico, está mediado por células-T y puede ser transferido a receptores normales, ya sea con células provenientes de...

Sistema linfoide y deficiencia proteica: deferenciación en timo y placas de Peyer / Lymphoid system and protein deficiency: differentiation in thymus gland and Peyers patches

En un modelo experimental de inmunodeficiencia provocada por déficit de proteínas, se demuestra: 1) en el timo, existencia de graves alteraciones en sus poblaciones celulares que se encuentran drmáticamente disminuídas: W3/13+ (pan- T), W3/25+ (CD4+) y OX8+ (DC8+), existiendo una población celular que contiene TdT como único marcador; 2) alteraciones en el ciclo celular de la IgA que permitieron demostrar in vivo la presencia de células pre-B en placas de Peyer con alteración marcada en las subpoblaciones T; 3) los mecanismos involucrados en la inmunidad mediada por células son dañados por el déficit de proteínas y continúan alterados después de que dicho déficit ha sido superado; 4) en el timo, la administración por via oral de una dieta de caseína al 20% restaura la población celular- T W3/13+ luego de 21 días, pero la subpoblación W3/25+ (CD4+) se encuentra muy disminuida; 5) al mismo tiempo se reinicia, en placas de Peyer, la diferenciación de los precursores de células plasmáticas de clase IgA, aunque se encuentra la diferenciación de los precursores de células plamáticas de clase IgA, aunque se encuentra alterado, tanto en ellas como en ganglio mesentérico, el número absoluto de células que expresan y contienen IgA, así como el de las células T maduras, especialmente la población CD4+; 6) el dearrollo de un mecanismo de tolerancia a dextrina que es antígeno-específico, está mediado por células-T y puede ser transferido a receptores normales, ya sea con células provenientes de... (AU)