RESUMEN
Exosomes are extracellular vesicles derived from the endosomal compartment, which are released by all kinds of eukaryotic and prokaryotic organisms. These vesicles contain a variety of biomolecules that differ both in quantity and type depending on the origin and cellular state. Exosomes are internalized by recipient cells, delivering their content and thus contributing to cell-cell communication in health and disease. During infections exosomes may exert a dual role, on one hand, they can transmit pathogen-related molecules mediating further infection and damage, and on the other hand, they can protect the host by activating the immune response and reducing pathogen spread. Selective packaging of pathogenic components may mediate these effects. Recently, quantitative analysis of samples by omics technologies has allowed a deep characterization of the proteins, lipids, RNA, and metabolite cargoes of exosomes. Knowledge about the content of these vesicles may facilitate their therapeutic application. Furthermore, as exosomes have been detected in almost all biological fluids, pathogenic or host-derived components can be identified in liquid biopsies, making them suitable for diagnosis and prognosis. This review attempts to organize the recent findings on exosome composition and function during viral, bacterial, fungal, and protozoan infections, and their contribution to host defense or to pathogen spread. Moreover, we summarize the current perspectives and future directions regarding the potential application of exosomes for prophylactic and therapeutic purposes.
Asunto(s)
Enfermedades Transmisibles , Exosomas , Humanos , Exosomas/metabolismo , Comunicación Celular , Enfermedades Transmisibles/terapia , Inmunoterapia , BiologíaRESUMEN
Nowadays, Coronavirus disease (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is one of the most important health problems. The dynamics and nature of humoral responses are relevant to determine the efficacy of both, diagnostic tests and developed vaccines. Since the role of IgA in the COVID-19 disease is not fully understood, we have systematically reviewed the scientific literature on antibody IgA immunity to SARS-CoV-2 to determine if IgA could be useful as a diagnostic tool or as a biomarker of severity. We systematically reviewed 736 abstracts and identified 38 manuscripts relevant to include in the meta-analysis. The seroprevalence of IgA in SARS-CoV-2 PCR (+) confirmed patients was 86.47% (CI: 5.27-178.21). Furthermore, we found out that IgA can be produced on the first days of infection (10 days) and IgA is detected until 75 days after symptomatic onset in some studies. We also observe that IgA production is stronger in severe patients compared with mild or asymptomatic patients. Our research noticed a possible association between IgA and protection; however, the possible role of IgA as a biomarker of protection or severity remains unclear.
Asunto(s)
COVID-19 , SARS-CoV-2 , Anticuerpos Antivirales , Biomarcadores , COVID-19/diagnóstico , COVID-19/epidemiología , Prueba de COVID-19 , Humanos , Inmunoglobulina A , Estudios SeroepidemiológicosRESUMEN
Human cytomegalovirus (HCMV) infection in children and young adults has been associated with changes in the innate immune system. We herein analyzed the possible effect of very long term HCMV infection on the expression of several NK cell receptors. Ninety HCMV-seropositive individuals were included and classified as young adults (n=30), elderly (n=30) and very elderly subjects (n=30). A peripheral blood sample was obtained and the expression of NK cell receptors (NKG2A, NKG2C, ILT2, CD161, KIR2DL1, KIR3DL1, and KIR3DL2) by NK and other lymphocyte subsets was assessed by flow cytometry. In addition, the frequency of the sixteen KIR genes was analyzed by polymerase chain reaction. We found a significant increase in the number of NKG2C+ NK and T cells in elderly individuals compared to young adults accompanied by an opposite trend in the number of NKG2A+ lymphocytes, and ILT2+ cells were also increased in elderly individuals. A significant increase in the levels of CD3-CD56+NKG2C+CD57+ cells was also detected in the elderly groups. Finally, KIR gene analysis revealed that the KIR genotype 2 was significantly less frequent in the elderly individuals. Our results support that long-term infection by HCMV exerts a significant progressive effect on the innate immune system.