Identification of the Kaposi\u27s Sarcoma-associated Herpesvirus (KSHV) Surface Glycoprotein Targets of Human KSHV-specific Neutralizing Antibody Responses

Kaposi’s sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8), is the etiological agent of Kaposi’s sarcoma (KS), and is also associated with two B cell malignancies, primary effusion lymphoma and multicentric Castleman\u27s disease. The distribution of KSHV varies globally with high prevalence in some areas of sub-Saharan Africa (SSA), where seroprevalence can be as high as 80%. It is estimated that nearly 44,000 new cases of KS emerge annually globally, with the highest incidents occurring in Africa, where KSHV is endemic. Currently, there is no prophylactic vaccine against KSHV, and efforts to develop prophylactic vaccines have been limited. Elicitation of neutralizing antibodies (nAbs) often correlates with protection during viral infections in humans, but it is not clear whether nAbs against KSHV will also convey protection against infection. KSHV initiates infection via interaction with various receptors on the surface of target cells, which is primarily mediated by multiple viral glycoproteins embedded in the viral envelope. These glycoproteins play important roles in virion attachment and entry into target cells, therefore they could be potential targets for KSHV-specific nAbs.Characterization of the human neutralizing antibody responses against KSHV envelope glycoproteins and identifying the targets of these antibodies, are needed for designing an effective vaccine against KSHV. KSHV virions incorporate eight glycoproteins into their envelope: ORF8 (gB), ORF28, ORF68, ORF22 (gH), ORF47 (gL), ORF39 (gM), ORF53 (gN) and gpK8.1. Through testing the ability of each KSHV glycoprotein in recognizing/adsorbing KSHV-specific nAbs by this study, it was determined that multiple KSHV glycoproteins were able to bind to these antibodies in a majority of KSHV infected individuals. In addition, the ability of each KSHV glycoprotein in depleting the KSHV nAbs from KSHV positive plasma varied among individuals. Among all the KSHV envelope glycoproteins, gH/gL complex showed high adsorption/recognition levels of KSHV-specific nAbs in 80% of the participants analyzed. These findings suggest that nAbs responses are variable in KSHV infected individuals, and multiple KSHV envelope glycoproteins are the targets of KSHV-specific nAbs, with gH/gL complex being the most predominant target, which can serve as a potential target antigen for developing prophylactic vaccines against KSHV. Advisor: Charles Woo

The Kaposi’s Sarcoma-Associated Herpesvirus (KSHV) gH/gL Complex Is the Predominant Neutralizing Antigenic Determinant in KSHV-Infected Individuals

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi’s sarcoma (KS), one of the most prevalent cancers of people living with HIV/AIDS in sub-Saharan Africa. The seroprevalence for KSHV is high in the region, and no prophylactic vaccine against the virus is available. In this study, we characterized the antigenic targets of KSHV-specific neutralizing antibodies (nAbs) in asymptomatic KSHV-infected individuals and KS patients with high nAbs titers. We quantified the extent to which various KSHV envelope glycoproteins (gB, ORF28, ORF68, gH, gL, gM, gN and gpK8.1) adsorbed/removed KSHV-specific nAbs from the plasma of infected individuals. Our study revealed that plasma from a majority of KSHV neutralizers recognizes multiple viral glycoproteins. Moreover, the breadth of nAbs responses against these viral glycoproteins varies among endemic KS, epidemic KS and asymptomatic KSHV-infected individuals. Importantly, among the KSHV glycoproteins, the gH/gL complex, but neither gH nor gL alone, showed the highest adsorption of KSHV-specific nAbs. This activity was detected in 80% of the KSHV-infected individuals regardless of their KS status. The findings suggest that the gH/gL complex is the predominant antigenic determinant of KSHV-specific nAbs. Therefore, gH/gL is a potential target for development of KSHV prophylactic vaccines

Viral and Immunological Analytes are Poor Predictors of the Clinical Treatment Response in Kaposi’s Sarcoma Patients

Kaposi’s sarcoma-associated herpes virus (KSHV) is the etiologic agent for Kaposi’s sarcoma (KS). The prognostic utility of KSHV and HIV-1 (human immunodeficiency virus) viremia as well as immunological parameters in clinical management of participants with KS is unclear. The objective of this study was to investigate viral and immunological parameters as predictors of KS treatment responses in participants with KS from sub-Saharan Africa (SSA). Plasma KSHV-DNA, HIV-1 viral load, total anti-KSHV antibody, KSHV-neutralizing antibody (nAb), cytokine/chemokine levels, and T-cell differentiation subsets were quantified before and after KS treatment in 13 participants with KS and in 13 KSHV-infected asymptomatic control individuals. One-way analysis of variance and the Mann-Whitney t-test were used to assess differences between groups where p-values \u3c 0.05 were considered significant. Subjects with patch and plaque KS lesions responded more favorably to treatment than those with nodular lesions. Pre-treatment and post-treatment levels of plasma KSHV-DNA, HIV-1 viral load, KSHV-Ab responses, cytokines, and T-cell populations did not predict the KS treatment response. Elevated KSHV-humoral and cytokine responses persisted in participants with KS despite a clinical KS response. While patch and plaque KS lesions were more common among treatment responders, none of the analyzed viral and immunological parameters distinguished responders from non-responders at baseline or after treatment

The Kaposi’s Sarcoma-Associated Herpesvirus (KSHV) gH/gL Complex Is the Predominant Neutralizing Antigenic Determinant in KSHV-Infected Individuals

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiological agent of Kaposi’s sarcoma (KS), one of the most prevalent cancers of people living with HIV/AIDS in sub-Saharan Africa. The seroprevalence for KSHV is high in the region, and no prophylactic vaccine against the virus is available. In this study, we characterized the antigenic targets of KSHV-specific neutralizing antibodies (nAbs) in asymptomatic KSHV-infected individuals and KS patients with high nAbs titers. We quantified the extent to which various KSHV envelope glycoproteins (gB, ORF28, ORF68, gH, gL, gM, gN and gpK8.1) adsorbed/removed KSHV-specific nAbs from the plasma of infected individuals. Our study revealed that plasma from a majority of KSHV neutralizers recognizes multiple viral glycoproteins. Moreover, the breadth of nAbs responses against these viral glycoproteins varies among endemic KS, epidemic KS and asymptomatic KSHV-infected individuals. Importantly, among the KSHV glycoproteins, the gH/gL complex, but neither gH nor gL alone, showed the highest adsorption of KSHV-specific nAbs. This activity was detected in 80% of the KSHV-infected individuals regardless of their KS status. The findings suggest that the gH/gL complex is the predominant antigenic determinant of KSHV-specific nAbs. Therefore, gH/gL is a potential target for development of KSHV prophylactic vaccines

Hoarseness as the Presenting Symptom of Visceral Leishmaniasis with Muco-Cutaneous Lesions: A Case Report

  Herein, a 28-year-old man with hoarseness, skin and oral lesions is presented. At the time of admission, the patient had an erythematous plaque on his chin near his lower lip and an erythematous-violaceous plaque on his palate near the open-ing of the pharynx and 20 kg weight lost in last one year. The biopsy of his skin lesions by hematoxylin and eosin staining revealed an infiltration of the dermis by lymphoplasma and histiocytic cells with a loose granuloma formation sugges-tive of leishmaniasis. Biopsy of mucosal lesions revealed Leishman bodies in dermis. PCR was performed on the specimens of skin, bone marrow, mucosa, and saliva, the results were positive. The pathogenic agent was identified as Leishmania major by the nested PCR. Serologic tests including direct agglutination test (DAT) and indirect immunofluorescence test (IFAT) were positive with high titers of anti-L. infantum antibodies (1:102400 versus 1:800, respectively), indicative of visceral involvement. The patient responded to a combination of miltefosine and meglumine antimoniate (Glucantime®). Visceral involvement due to L. major is rarely reported. To the best of our knowledge, probably hoarseness due to L. major has not been previously reported from Iran

Viral and Immunological Analytes are Poor Predictors of the Clinical Treatment Response in Kaposi’s Sarcoma Patients

Kaposi’s sarcoma-associated herpes virus (KSHV) is the etiologic agent for Kaposi’s sarcoma (KS). The prognostic utility of KSHV and HIV-1 (human immunodeficiency virus) viremia as well as immunological parameters in clinical management of participants with KS is unclear. The objective of this study was to investigate viral and immunological parameters as predictors of KS treatment responses in participants with KS from sub-Saharan Africa (SSA). Plasma KSHV-DNA, HIV-1 viral load, total anti-KSHV antibody, KSHV-neutralizing antibody (nAb), cytokine/chemokine levels, and T-cell differentiation subsets were quantified before and after KS treatment in 13 participants with KS and in 13 KSHV-infected asymptomatic control individuals. One-way analysis of variance and the Mann-Whitney t-test were used to assess differences between groups where p-values \u3c 0.05 were considered significant. Subjects with patch and plaque KS lesions responded more favorably to treatment than those with nodular lesions. Pre-treatment and post-treatment levels of plasma KSHV-DNA, HIV-1 viral load, KSHV-Ab responses, cytokines, and T-cell populations did not predict the KS treatment response. Elevated KSHV-humoral and cytokine responses persisted in participants with KS despite a clinical KS response. While patch and plaque KS lesions were more common among treatment responders, none of the analyzed viral and immunological parameters distinguished responders from non-responders at baseline or after treatment

Sensitive areas for sampling.

<p>A) eyelid B) around the eye C) ear D) on the lips.</p

Clinical profiles of 119 cutaneous leishmaniasis patients.

<p>Clinical profiles of 119 cutaneous leishmaniasis patients.</p

Schematic presentation of sampling lesions with tape strip discs, DNA isolation and further identification of <i>Leishmania</i> species.

<p>1) patient´s lesion 2) disc 3) disc applied to patient´s lesion 4) even pressure applied on lesion using a plunger 5) sterile removal of disc from the lesion 6) DNA isolation from disc 7) confirmation of <i>Leishmania</i> by kDNA1 8) species-specific identification (PCR ITS-RFLP).</p

Disease duration, gender distribution and infecting species of <i>Leishmania</i> in CL patients with acute, chronic or healed disease.

<p>Disease duration, gender distribution and infecting species of <i>Leishmania</i> in CL patients with acute, chronic or healed disease.</p