Células natural killer e vigilância imunológica

Abstract

Objectives: To analyze the importance of natural killer cells, their killer immunoglobulin-like receptors (KIR) and genes in autoimmunity and in the immune surveillance against infectious agents and stem cells transplantation. The characteristics and polymorphisms of the KIR genes and receptors in the Brazilian population is described. Sources:Textbooks, review articles and recent scientific articles are cited and listed in the references. Summary of the findings:KIR genes and haplotypes within a Brazilian Caucasian population were surveyed and analyzed to assess the future relationship of this system with diseases. Of 116 voluntary bone marrow donors, we identified 32 genotypes with frequencies of A and B haplotypes of 51 and 49%, respectively. A comparative analysis was performed between these genotypes and those from other populations. Conclusions:Innate immunity is an important anti-infectious barrier in newborns. It is independent of both cellular and humoral immunity, can be faster and confers great advantage in early age. At the same time, it stimulates CD8 T lymphocytes to act and amplify the immunological protection network. Nevertheless, as in the majority of situations in which immunity is activated, it can also be harmful, damaging the body through autoimmune mechanisms or even, through its absence, creating space for infectious agents to act free. Our study of a control group for KIR genotype and haplotypes in Brazilian Caucasoids could be used in future analyse of diseases related to these genes. J Pediatr (Rio J). 2008;84(4 Suppl):S58-67:KIR genes, natural killer cells, KIR genotypes in Brazilian Caucasoids.

Natural Killer cells role in embryonic implantion

“…Moffet and Shreeve, 6 as also Vacca et al, 7 were chosen because they extensively described uNK cells and their relationship to the endometrium. The final project of Nuñez et al 8 and the article of Jobim and Jobim, 9 presented in general the function of the immune system and the performance of NK. Costa's 10 thesis raised the problem and a greater understanding of the theme.…”

“…4 A complex cellular network interacts to discriminate "the self from the non-self" in order to destroy foreign bodies, tumor and transplanted cells. 9 These pathogens produce substances called antigens, which lead to the recognition and response of the immune system. 5 Immunity is divided into innate and acquired.…”

“…In addition, they present CD16 and CD56 surface antigens, but they do not manifest antibody and T-cell receptors. 5,9 NKs belong to innate immunity and therefore act in immunological surveillance, corresponding to approximately 10 to 20% of circulating lymphocytes. 7,9 These cells act in two ways: through the production of cytokines that stimulate macrophages to destroy infected cells or to recognize these cells and to apoptose them.…”

“…5,9 NKs belong to innate immunity and therefore act in immunological surveillance, corresponding to approximately 10 to 20% of circulating lymphocytes. 7,9 These cells act in two ways: through the production of cytokines that stimulate macrophages to destroy infected cells or to recognize these cells and to apoptose them. 5,14 In the first hypothesis, NK stimulate phagocytic cells through the release of interferon and (INF -y) in response to interleukin-12 (IL-12) released by macrophages during inflammation process (Figure 1).…”

“…5,14 In the first hypothesis, NK stimulate phagocytic cells through the release of interferon and (INF -y) in response to interleukin-12 (IL-12) released by macrophages during inflammation process (Figure 1). 5,9 However, infected cells identification and subsequently their programmed death is caused by MHC class I absence in membrane, triggering NK activation -process called missing self. 5,10 Although IL-12 is the main cytokine activator of NK, others such as interleukin-15 (IL-15), interleukin-18 (IL-18) and high concentration of interleukin-2 (IL-2) also lymphocytes.…”