B cells expressing IL-10 mRNA modulate memory T cells after DNA-Hsp65 immunization

In DNA vaccines, the gene of interest is cloned into a bacterial plasmid that is engineered to induce protein production for long periods in eukaryotic cells. Previous research has shown that the intramuscular immunization of BALB/c mice with a naked plasmid DNA fragment encoding the Mycobacterium leprae 65-kDa heat-shock protein (pcDNA3-Hsp65) induces protection against M. tuberculosis challenge. A key stage in the protective immune response after immunization is the generation of memory T cells. Previously, we have shown that B cells capture plasmid DNA-Hsp65 and thereby modulate the formation of CD8+ memory T cells after M. tuberculosis challenge in mice. Therefore, clarifying how B cells act as part of the protective immune response after DNA immunization is important for the development of more-effective vaccines. The aim of this study was to investigate the mechanisms by which B cells modulate memory T cells after DNA-Hsp65 immunization. C57BL/6 and BKO mice were injected three times, at 15-day intervals, with 100 µg naked pcDNA-Hsp65 per mouse. Thirty days after immunization, the percentages of effector memory T (TEM) cells (CD4+ and CD8+/CD44high/CD62Llow) and memory CD8+ T cells (CD8+/CD44high/CD62Llow/CD127+) were measured with flow cytometry. Interferon γ, interleukin 12 (IL-12), and IL-10 mRNAs were also quantified in whole spleen cells and purified B cells (CD43−) with real-time qPCR. Our data suggest that a B-cell subpopulation expressing IL-10 downregulated proinflammatory cytokine expression in the spleen, increasing the survival of CD4+ TEM cells and CD8+ TEM/CD127+ cells.

Sistema imunológico: atualidades e perspectivas para a prática clínica / Immune system: present time and perspectives for clinical practice

O sistema imunológico (SI), à semelhança do sistema nervoso, tem uma participação central na biologia do Homo sapiens sapiens (sic), tendo na comunicação um dos esteios para sua organização e funcionamento. Além de ser capaz de distinguir o que é próprio (self) do que é não-próprio (non-self), o SI estrutura-se em rede, processando informações de modo a permitir o aprendizado e o desenvolvimento da memória, aspectos fundamentais para a relação do organismo com o meio ambiente, com importantes implicações no adoecimento humano. Com base nestas considerações, objetiva-se, no presente manuscrito, apresentar, de modo sintético, os principais aspectos do sistema imunológico.

The immune system (IS), like the nervous system, plays a central role in the biology of Homo sapiens sapiens (sic), eith communication as a base for its organization and operation. In addition to an ability to distinguish self from non-self, the IS structures itself in a network, processing information in a way to allow learning and the development of memory, fundamental aspects in the organim's relation with the environment, with important implications in human illnesses. Based on these considerations, this review aims to present, in a synthetic manner, the principal aspects of the immune system.

Linking immunity and hematopoiesis by bone marrow T cell activity

Two different levels of control for bone marrow hematopoiesis are believed to exist. On the one hand, normal blood cell distribution is believed to be maintained in healthy subjects by an "innate" hematopoietic activity, i.e., a basal intrinsic bone marrow activity. On the other hand, an "adaptive" hematopoietic state develops in response to stress-induced stimulation. This adaptive hematopoiesis targets specific lineage amplification depending on the nature of the stimuli. Unexpectedly, recent data have shown that what we call "normal hematopoiesis" is a stress-induced state maintained by activated bone marrow CD4+ T cells. This T cell population includes a large number of recently stimulated cells in normal mice whose priming requires the presence of the cognate antigens. In the absence of CD4+ T cells or their cognate antigens, hematopoiesis is maintained at low levels. In this review, we summarize current knowledge on T cell biology, which could explain how CD4+ T cells can help hematopoiesis, how they are primed in mice that were not intentionally immunized, and what maintains them activated in the bone marrow.

Participación de la apoptosis en los procesos inmunológicos / Participation of apoptosis in immunologic processes

Apoptosis is a biological process that leads certain cells to die in a controlled fashion. Its biochemical manifestation is DNA fragmentation due to the action of an endonuclease and morphological consequences is the formation of apoptic bodies, seen with lught or electron microscopy. Apoptosis is universally important in embryogenesis and morphologenesis of all tissues. Lately, a fundamental role of apoptosis in the physiology and physiopathology of immunological events has been uncovered. This review details the role of apoptosis in the development of auto-tolerance, immunological memory and AIDS pathogenesis

Mecanismos inmunológicos en las enfermedades infecciosas / Immunologycal mecanisms of infectious diseases

Los mecanismos de inmunidad contra las infecciones bacterianas, parasitarias y virales son extremadamente complejos y tienen como principal función la eliminación de los microorganismos patógenos. Los sistemas de defensa no específicos contra las bacterias, son proporcionados por los granulocitos, que ingieren y matan a la mayoría de los patógenos. Sin embargo, se necesita de la inmunidad específica contra bacterias encapsuladas o intracelulares y contra parásitos y virus para eliminar a éstos, lo cual requiere del desarrollo de anticuerpos a través de la inmunidad humoral y de la inmunidad celular que puede desencadenar la actividad microbicida de los macrófagos. En muchas infecciones humanas, todos los mecanismos inmunológicos (anticuerpos, complemento, linfocitos, granulocitos y macrófagos) son esenciales para desarrollar una inmunidad protectora contra muchos microorganismos patógenos