ABSTRACT
Short, unique, in-frame deletions were consistently detected within p6gag sequences obtained over time from three of eight HIV-1-infected long-term nonprogressors (Alexander, L., Weiskopf, E., Greenough, T.C., Gaddis, N.C., Auerbach, M.R., Malim, M.H., O'Brien, S.J., Walker, B.D., Sullivan, J.L., Desrosiers, R.C., 2000. Unusual polymorphisms in Human Immunodeficiency Virus Type 1 associated with nonprogressive infection. J. Virol. 74, 4361-4376). Using PCR mutagenesis, we created 11 mutant forms of SIV239 and 8 mutant forms of HIV-1 NL4-3 with serial 2 amino acid deletions within p6gag downstream of the PTAP late domain. Nine of the 11 SIV239 mutants assembled and released virion particles similar to wild-type, displayed wild-type infectivity, and replicated similar to wild-type SIV239 in cultured cells. Two of the 11 SIV239 mutants, both involving D at position 21, were grossly defective for intracellular gag accumulation and did not replicate detectably in cultured cells. Similar to the 9 SIV239 mutants, 7 of the 8 HIV-1 mutants replicated well in cultured cells. Only the mutant deleted of ES at positions 19 and 20, immediately adjacent to the PTAP sequence, was markedly impaired in its replicative capacity. These results demonstrate an overall high tolerance of SIV and HIV to two amino acid deletions within p6gag downstream of the late domain.
Subject(s)
Gene Products, gag/genetics , HIV-1/genetics , HIV-1/physiology , Sequence Deletion , Simian Immunodeficiency Virus/genetics , Simian Immunodeficiency Virus/physiology , Amino Acid Sequence , Animals , Cell Line , Cells, Cultured , Gene Products, gag/biosynthesis , Gene Products, gag/physiology , HIV Core Protein p24/biosynthesis , Humans , Lymphocytes/virology , Macaca mulatta , Molecular Sequence Data , Mutagenesis , Polymerase Chain Reaction , Virus Assembly , Virus Replication , gag Gene Products, Human Immunodeficiency VirusABSTRACT
Shwachman-Diamond syndrome (OMIM 260400) is a multisystemic disorder characterized by pancreatic insufficiency, bone marrow dysfunction, skeletal abnormalities and immune dysfunction. Prompted by the case of a 13-year-old girl with Shwachman-Diamond syndrome who presented with pneumonia attributable to Pseudomonas aeruginosa, we review infectious complications of this disease. Pneumonia, recurrent otitis media and skin infections/abscesses constitute the majority of infections among these children.
Subject(s)
Bone Marrow Diseases/complications , Exocrine Pancreatic Insufficiency/complications , Opportunistic Infections/etiology , Adolescent , Bacterial Infections/etiology , Bone Marrow Diseases/genetics , Exocrine Pancreatic Insufficiency/genetics , Female , Humans , Syndrome , Virus Diseases/etiologyABSTRACT
Neutralizing antibody titers have been correlated with protection following vaccination against many viral pathogens. The logical target of protective antibody responses elicited by potential HIV vaccines should be the viral Env spike on the surface of the virion. However, the potency and titers of neutralizing antibodies that arise during HIV infection are generally discouragingly low and the antibodies that do arise recognize mainly autologous virus. This is thought to be a result of a combination of immunodominance of hypervariable regions of the Env protein that can easily escape neutralization, antibody reactivity to gp160 "decoy" protein in cell surface debris or monomeric gp120, conformational constraints within the Env trimer that create unfavorable antibody binding conditions and extensive glycosylation of the exposed regions of Env within the trimer. This review will describe current knowledge regarding glycosylation as a mechanism of neutralization resistance and discuss experimental approaches used to overcome this resistance. Part of the strategy toward development of an optimally immunogenic Env spike will likely require modification of Env glycosylation.
