Estudo de marcadores imunológicos em células Natural Killer – NK em homens e mulheres saudáveis

Abstract

Natural killer - NK cells are lymphocytes that are characterized by the expression of CD3- CD16+ CD56+ markers, which perform innate activities such as antiviral, antimicrobial and antitumor defense, therefore they have a promising clinical importance, where their activity in the body is usually mediated by activating signals or inhibitory. In this way, the NK cell can express natural cytotoxicity receptors on its cell membrane, such as NKP44, NKP46 and CD94. Once activated, these cells can secrete cytokines such as IL-10 and INF-ɣ or mediate the death of harmful agents by the process of degranulation of granzyme and perforin. It is known that sexual dimorphism plays an important role in the direct involvement of the immune system and NK cells, in addition, the aging process acts to produce physiological differences, resulting in immunological differences. Thus, the objective of this work was to evaluate the expression of immunological markers of surface and intracellular NK cells in males and females. Therefore, peripheral blood from 10 healthy donors was collected, male (n = 5) and female (n = 4), and subsequently evaluated by flow cytometry. The frequency and mean fluorescence intensity variables were analyzed to express the following NK cell markers: NKP44. NKP46, CD94, CD107a, IL-10, INF-ɣ, granzyme and perforin in both sexes. An increase in the population frequency of NK cells was observed, in addition to a higher mean fluorescence intensity of CD107a and production of perforin in males. The expression and production of NKP44, NKP46, CD94, IL-10, INF-ɣ and granzyme was unchanged in both sexes. Thus, it is suggested that under homeostatic conditions, NK cells may present differences in expression and / or fluorescence intensity of constitutive markers and important for their cytotoxic function, such as CD107a and perforin, related to sexual dimorphism. This study is unprecedented because studies that seek to analyze immunological markers and their differences in expression and fluorescence intensity in sexual dimorphism are rare.