RESUMEN
Certain HLA-B antigens have been associated with lack of progression to AIDS. HLA-B alleles can be divided into two mutually exclusive groups based on the expression of the molecular epitopes HLA-Bw4 and HLA-Bw6. Notably, in addition to its role in presenting viral peptides for immune recognition, the HLA-Bw4, but not HLA-Bw6, motif functions as a ligand for a natural killer cell inhibitory receptor (KIR). Here, we show that profound suppression of HIV-1 viremia is significantly associated with homozygosity for HLA-B alleles that share the HLA-Bw4 epitope. Furthermore, homozygosity for HLA-Bw4 alleles was also significantly associated with the ability to remain AIDS free and to maintain a normal CD4 T cell count in a second cohort of HIV-1-infected individuals with well defined dates of seroconversion. This association was independent of the presence of a mutation in CC chemokine receptor 5 (CCR5) associated with resistance to HIV-1 infection, and it was independent of the presence of HLA alleles that could potentially confound the results. We conclude that homozygosity for HLA-Bw4-bearing B alleles is associated with a significant advantage and that the HLA-Bw4 motif is important in AIDS pathogenesis.
Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/genética , Síndrome de Inmunodeficiencia Adquirida/inmunología , VIH-1/inmunología , Antígenos HLA-B/genética , Antígenos HLA-B/inmunología , Homocigoto , Viremia/inmunología , Síndrome de Inmunodeficiencia Adquirida/virología , Adulto , Alelos , Recuento de Linfocito CD4 , Estudios de Cohortes , Progresión de la Enfermedad , Epítopos/inmunología , Femenino , Frecuencia de los Genes , Seropositividad para VIH/genética , Seropositividad para VIH/inmunología , Seropositividad para VIH/virología , VIH-1/fisiología , Antígenos HLA-C/genética , Antígenos HLA-C/inmunología , Humanos , Células Asesinas Naturales/inmunología , Masculino , Persona de Mediana Edad , Mutación/genética , Receptores CCR5/genética , Receptores Inmunológicos/inmunología , Receptores KIR , Factores de Tiempo , Carga Viral , Viremia/genética , Viremia/virologíaRESUMEN
Grains with pseudo-fivefold symmetry have been observed in nickel prepared by thermnal decomposition of nickel carbonyl. These grains were studied by transmission electron microscopy and electron diffraction Techniques. The defect structure and composite symmetry varied within a given sample, and the size of the grains varied with the thickness of the sample.