Interaction of a dengue virus NS1-derived peptide with the inhibitory receptor KIR3DL1 on natural killer cells.

Killer immunoglobulin-like receptors (KIRs) interact with human leucocyte antigen (HLA) class I ligands and play a key role in the regulation and activation of NK cells. The functional importance of KIR-HLA interactions has been demonstrated for a number of chronic viral infections, but to date only a few studies have been performed in the context of acute self-limited viral infections. During our investigation of CD8(+) T cell responses to a conserved HLA-B57-restricted epitope derived from dengue virus (DENV) non-structural protein-1 (NS1), we observed substantial binding of the tetrameric complex to non-T/non-B lymphocytes in peripheral blood mononuclear cells (PBMC) from a long-standing clinical cohort in Thailand. We confirmed binding of the NS1 tetramer to CD56(dim) NK cells, which are known to express KIRs. Using depletion studies and KIR-transfected cell lines, we demonstrated further that the NS1 tetramer bound the inhibitory receptor KIR3DL1. Phenotypical analysis of PBMC from HLA-B57(+) subjects with acute DENV infection revealed marked activation of NS1 tetramer-binding natural killer (NK) cells around the time of defervescence in subjects with severe dengue disease. Collectively, our findings indicate that subsets of NK cells are activated relatively late in the course of acute DENV illness and reveal a possible role for specific KIR-HLA interactions in the modulation of disease outcomes.

Waning and boosting of antibody Fc-effector functions upon SARS-CoV-2 vaccination.

Since the emergence of SARS-CoV-2, vaccines targeting COVID-19 have been developed with unprecedented speed and efficiency. CoronaVac, utilising an inactivated form of the COVID-19 virus and the mRNA26 based Pfizer/BNT162b2 vaccines are widely distributed. Beyond the ability of vaccines to induce production of neutralizing antibodies, they might lead to the generation of antibodies attenuating the disease by recruiting cytotoxic and opsonophagocytic functions. However, the Fc-effector functions of vaccine induced antibodies are much less studied than virus neutralization. Here, using systems serology, we follow the longitudinal Fc-effector profiles induced by CoronaVac and BNT162b2 up until five months following the two-dose vaccine regimen. Compared to BNT162b2, CoronaVac responses wane more slowly, albeit the levels remain lower than that of BNT162b2 recipients throughout the entire observation period. However, mRNA vaccine boosting of CoronaVac responses, including response to the Omicron variant, induce significantly higher peak of antibody functional responses with increased humoral breadth. In summary, we show that vaccine platform-induced humoral responses are not limited to virus neutralization but rather utilise antibody dependent effector functions. We demonstrate that this functionality wanes with different kinetics and can be rescued and expanded via boosting with subsequent homologous and heterologous vaccination.

Waning and boosting of functional humoral immunity to SARS-CoV-2.

Since the emergence of the SARS-CoV-2 virus, we have witnessed a revolution in vaccine development with the rapid emergence and deployment of both traditional and novel vaccine platforms. The inactivated CoronaVac vaccine and the mRNA-based Pfizer/BNT162b2 vaccine are among the most widely distributed vaccines, both demonstrating high, albeit variable, vaccine effectiveness against severe COVID-19 over time. Beyond the ability of the vaccines to generate neutralizing antibodies, antibodies can attenuate disease via their ability to recruit the cytotoxic and opsinophagocytic functions of the immune response. However, whether Fc-effector functions are induced differentially, wane with different kinetics, and are boostable, remains unknown. Here, using systems serology, we profiled the Fc-effector profiles induced by the CoronaVac and BNT162b2 vaccines, over time. Despite the significantly higher antibody functional responses induced by the BNT162b2 vaccine, CoronaVac responses waned more slowly, albeit still found at levels below those present in the systemic circulation of BNT162b2 immunized individuals. However, mRNA boosting of the CoronaVac vaccine responses resulted in the induction of significantly higher peak antibody functional responses with increased humoral breadth, including to Omicron. Collectively, the data presented here point to striking differences in vaccine platform-induced functional humoral immune responses, that wane with different kinetics, and can be functionally rescued and expanded with boosting.

NK cells in HIV-1 infection: evidence for their role in the control of HIV-1 infection.

Increasing evidence supports the notion that the innate immune response, and in particular, natural killer cells play a central role in determining the quality of the host immune response to infection. In this review we highlight recent evidence that suggests that NK cells influence the clinical fate of HIV-infected individuals.

Fc receptor-mediated phagocytosis in tissues as a potent mechanism for preventive and therapeutic HIV vaccine strategies.

Although the development of a fully protective HIV vaccine is the ultimate goal of HIV research, to date only one HIV vaccine trial, the RV144, has successfully induced a weakly protective response. The 31% protection from infection achieved in the RV144 trial was linked to the induction of nonneutralizing antibodies, able to mediate antibody-dependent cell-mediated cytotoxicity (ADCC), suggestive of an important role of Fc-mediated functions in protection. Similarly, Fc-mediated antiviral activity was recently shown to play a critical role in actively suppressing the viral reservoir, but the Fc effector mechanisms within tissues that provide protection from or after infection are largely unknown. Here we aimed to define the landscape of effector cells and Fc receptors present within vulnerable tissues. We found negligible Fc receptor-expressing natural killer cells in the female reproductive and gastrointestinal mucosa. Conversely, Fc receptor-expressing macrophages were highly enriched in most tissues, but neutrophils mediated superior antibody-mediated phagocytosis. Modifications in Fc domain of VRC01 antibody increased phagocytic responses in both phagocytes. These data suggest that non-ADCC-mediated mechanisms, such as phagocytosis and neutrophil activation, are more likely to play a role in preventative vaccine or reservoir-eliminating therapeutic approaches.

Prevention of SHIV transmission by topical IFN-ß treatment.

Understanding vaginal and rectal HIV transmission and protective cellular and molecular mechanisms is critical for designing new prevention strategies, including those required for an effective vaccine. The determinants of protection against HIV infection are, however, poorly understood. Increasing evidence suggest that innate immune defenses may help protect mucosal surfaces from HIV transmission in highly exposed, uninfected subjects. More recent studies suggest that systemically administered type 1 interferon protects against simian immunodeficiency virus infection of macaques. Here we hypothesized that topically applied type 1 interferons might stimulate vaginal innate responses that could protect against HIV transmission. We therefore applied a recombinant human type 1 interferon (IFN-ß) to the vagina of rhesus macaques and vaginally challenged them with pathogenic simian/human immunodeficiency virus (SHIV). Vaginal administration of IFN-ß resulted in marked local changes in immune cell phenotype, increasing immune activation and HIV co-receptor expression, yet provided significant protection from SHIV acquisition as interferon response genes were also upregulated. These data suggest that protection from vaginal HIV acquisition may be achieved by activating innate mucosal defenses.

Substrate and cofactor binding to fluorescently labeled cytoplasmic malate dehydrogenase.

Cytoplasmic malate dehydrogenase (cMDH) is a key enzyme in several metabolic pathways. Though its activity has been examined extensively, there are lingering mechanistic uncertainties involving substrate and cofactor binding. To more completely understand this enzyme's interactions with cofactor and substrate ligands, a fluorescent reporter group was introduced into the enzyme's structure. This was accomplished by selective modification of Cys 110. The reaction placed an aminonaphthaline sulfonic acid group near the enzyme's active site. Substrate, inhibitor, and NAD binding activities were characterized using changes in this label's fluorescence. Results demonstrated that both substrate and cofactor molecules bound to the enzyme in the absence of their companion ligands. This is in contrast to strictly ordered cofactor then substrate binding as has been suggested by kinetic analyses of closely related enzymes. Binding results also indicated that the cofactor, NAD, bound to cMDH in a negatively cooperative manner, but substrates and the inhibitor, hydroxymalonate, bound non-cooperatively. Multiple substrate binding modes were identified and interactions between substrate and cofactor binding were found.

Dissociation of mitochondrial malate dehydrogenase into active soluble subunits.

Gel exclusion chromatographic studies demonstrate that cytosolic and mitochondrial malate dehydrogenases (cMDH and mMDH) dissociate into subunits in the presence of 0.1% of the non-ionic detergent Triton X-100 (TX-100). The presence of cofactor and catalytically competent cofactor-substrate pairs does not protect mMDH against this dissociation. In contrast, cMDH dimers resist dissociation in the presence of either addition. Since steady state kinetic studies indicate both enzymes are fully active in the presence of 0.1% TX-100, we conclude that quaternary structure is not a kinetically important feature of mMDH structure and cooperativity does not account for mMDH kinetic anomalies. In contrast, cooperativity is a reasonable explanation for cMDH kinetic properties even in the presence of 0.1% TX-100, since this enzyme's subunits associate in the presence of active site ligands. The existence of fully active mMDH subunits raises the possibility that this species rather than the dimer may be a constituent of proposed multi-enzyme complexes of the mitochondrion. Preliminary chromatographic experiments involving gently disrupted mitochondria have found MDH activity in differently sized complexes, all with molecular weights larger than the mMDH dimer but smaller than complexes anticipated for multi-enzyme complexes involving other enzymes and the mMDH dimer.

Presence of a phospholipase D (PLD) distinct from PLD1 or PLD2 in human neutrophils: immunobiochemical characterization and initial purification.

Utilizing the transphosphatidylation reaction catalyzed by phospholipase D (PLD) in the presence of a primary alcohol and the short-chain phospholipid PC8, we have characterized the enzyme from human neutrophils. A pH optimum of 7.8-8.0 was determined. PIP(2), EDTA/EGTA, and ATP were found to enhance basal PLD activity in vitro. Inhibitory elements were: oleate, Triton X-100, n-octyl-beta-glucopyranoside, divalent cations, GTPgammaS and H(2)O(2). The apparent K(m) for the butanol substrate was 0.1 mM and the V(max) was 6.0 nmol mg(-1) h(-1). Immunochemical analysis by anti-pan PLD antibodies revealed a neutrophil PLD of approximately 90 kDa and other bands recognized minimally by anti-PLD1 or anti-PLD2 antibodies. The 90-kDa protein is tyrosine-phosphorylated upon cell stimulation with GM-CSF and formyl-Met-Leu-Phe. Protein partial purification using column liquid chromatography was performed after cell subfractionation. Based on the enzyme's regulatory and inhibitory factors, and its molecular weight, these data indicate an enzyme isoform that might be different from the mammalian PLD1/2 forms described earlier. The present results lay the foundation for further purification of this granulocyte PLD isoform.

Hemangioma of penis and scrotum.

Hemangiomas of the genitalia are extremely rare. A hemangioma is self-limited and usually resolves spontaneously, therefore conservative treatment is generally recommended. However, genital hemangiomas may require surgical treatment if they become symptomatic. Herein we report a case of hemangioma of the penis and scrotum requiring surgical excision. The natural history and alternative treatments of hemangiomas are described.

Buried penis as a contraindication for circumcision.

Neonatal circumcision is a frequently performed procedure with rare complications. Buried penis is an infrequent congenital penile deformity. If unrecognized, circumcision of these infants may have serious consequences. Buried penis refers to a penile shaft that is buried below the surface of the prepubic skin because of an abnormally prominent suprapubic fat pad and dense fascial bands retracting and tethering the penis. Description of the entity and operative repair are discussed. Avoidance of neonatal circumcision in patients with buried penis is imperative to prevent worsening of the condition.

Efficacy and safety of rimexolone 1% ophthalmic suspension vs 1% prednisolone acetate in the treatment of uveitis.

PURPOSE: Two multicenter studies compared the efficacy and safety of rimexolone 1% ophthalmic suspension (Vexol 1%, Alcon) and 1% prednisolone acetate (Pred Forte, Allergan). METHODS: Patients with acute uveitis, recurrent iridocyclitis, or chronic uveitis treatable by topical corticosteroid were enrolled. Treatment regimen was one or two drops every hour during Week 1, every two hours during Week 2, four times a day during Week 3, and once a day for the last three days. Efficacy and safety were determined on Days 3, 4, 7 to 10, 14, 21, and 28. A poststudy evaluation was conducted 36 to 72 hours after treatment was stopped. RESULTS: When anterior chamber cell and flare were measured, rimexolone 1% was found to be as effective as 1% prednisolone. The largest difference observed between treatments was 0.5 score unit, not clinically significant. There were no statistically significant differences in cell scores in either study (P > .05). No statistically significant differences in flare scores were found except at Day 28 in Study One (P = .04). Also, prednisolone was found to be more likely than rimexolone to cause a clinically significant increase (10 mm Hg or more) in intraocular pressure (1.7 times more likely in Study One, eight times more likely in Study Two). CONCLUSION: Rimexolone 1% ophthalmic suspension is safe and effective for the treatment of uveitis.

Augmentation phalloplasty.

Aesthetic procedures can increase the girth and visual length of the penis. Dermal-fat grafts increase penile circumference without the complications that result from fat injections. Release of the suspensory ligaments with skin advancement may increase flaccid penile length. Suprapubic lipectomy and Z-plasty of a penoscrotal web enhance penile appearance. Accurate diagnosis and meticulous technique are mandatory.

Experience with vaginal reconstruction utilizing the modified Singapore flap.

Many types of vaginal reconstruction have been described, and we have employed several with varying degrees of success. All we have used seem to have drawbacks. In April 1989 Wee and Joseph from Singapore described a technique using neurovascular pudendal-thigh flaps as islands. Initially we used the procedure as described. Later we modified the approach by releasing the labia majora, allowing them to retract somewhat anteriorly, and rotating the flap into position. This procedure has been used in eight patients, in some instances under the most adverse circumstances in patients who have undergone multiple procedures and heavy irradiation (including intraoperative radiation) besides experiencing postoperative leakage of urine. Though we have had dehiscence and problems with infection and drainage in some of our patients, no flap has failed, contour is exceptionally good, and potential for function is satisfactory. The procedure requires less time and produces better results than any other technique employed by us in the more than 30 vaginal reconstructions we have carried out. The technique will be illustrated and clinical cases will be presented.

The European marriage pattern as solution and problem: households of the elderly in Verviers, Belgium, 1831.

"The essay considers the effects of marriage patterns on the support of the elderly with empirical evidence from Verviers, a small industrial city in nineteenth-century Belgium. The (Northwest) European Marriage Pattern offered a solution for those elderly who had children, especially those with large families, because coresidence with children was the main source of support. The larger community experienced a problem...in the form of large numbers of persons who never married or reached old age with no surviving children. Moreover, while those who had married were able to maintain their economic status, those who never married liquidated their property holdings and became boarders and lodgers in the households of nonkin."

Altered distribution of mucosal NK cells during HIV infection.

The human gut mucosa is a major site of human immunodeficiency virus (HIV) infection and infection-associated pathogenesis. Increasing evidence shows that natural killer (NK) cells have an important role in control of HIV infection, but the mechanism(s) by which they mediate antiviral activity in the gut is unclear. Here, we show that two distinct subsets of NK cells exist in the gut, one localized to intraepithelial spaces (intraepithelial lymphocytes, IELs) and the other to the lamina propria (LP). The frequency of both subsets of NK cells was reduced in chronic infection, whereas IEL NK cells remained stable in spontaneous controllers with protective killer immunoglobulin-like receptor/human leukocyte antigen genotypes. Both IEL and LP NK cells were significantly expanded in immunological non-responsive patients, who incompletely recovered CD4+ T cells on highly active antiretroviral therapy (HAART). These data suggest that both IEL and LP NK cells may expand in the gut in an effort to compensate for compromised CD4+ T-cell recovery, but that only IEL NK cells may be involved in providing durable control of HIV in the gut.

Loss of mucosal CD103+ DCs and IL-17+ and IL-22+ lymphocytes is associated with mucosal damage in SIV infection.

Human immunodeficiency virus (HIV) and Simian immunodeficiency virus (SIV) disease progression is associated with multifocal damage to the gastrointestinal tract epithelial barrier that correlates with microbial translocation and persistent pathological immune activation, but the underlying mechanisms remain unclear. Investigating alterations in mucosal immunity during SIV infection, we found that damage to the colonic epithelial barrier was associated with loss of multiple lineages of interleukin (IL)-17-producing lymphocytes, cells that microarray analysis showed expressed genes important for enterocyte homeostasis, including IL-22. IL-22-producing lymphocytes were also lost after SIV infection. Potentially explaining coordinate loss of these distinct populations, we also observed loss of CD103+ dendritic cells (DCs) after SIV infection, which associated with the loss of IL-17- and IL-22-producing lymphocytes. CD103+ DCs expressed genes associated with promotion of IL-17/IL-22+ cells, and coculture of CD103+ DCs and naïve T cells led to increased IL17A and RORc expression in differentiating T cells. These results reveal complex interactions between mucosal immune cell subsets providing potential mechanistic insights into mechanisms of mucosal immune dysregulation during HIV/SIV infection, and offer hints for development of novel therapeutic strategies to address this aspect of AIDS virus pathogenesis.