Background: Naturally acquired immune responses to Plasmodium falciparum merozoite surface protein 3 (MSP3) and UB05 are implicated in semi immunity in populations living in malaria endemic areas. Thus designing chimeric malaria vaccine candidates involving MSP-3 and UB05 displayed upon the surface of a phage in its native form could potentiate their immunogenicity and antigenicity. In this study, we have engineered both MSP3 and UB05 upon the Qβ and assessed their antigenicity with plasma from children living in a high malaria transmission region of Cameroon. Methods: The surface of the RNA coliphage Qβ was genetically modified to display three Plasmodium falciparum derived immunogens including MSP3, UB05 and a chimera of the two UB05-MSP3. The resultant recombinant phages including QβMSP3, QβUB05 and QβUB05-MSP3 with surface displayed malaria immunogens were produced after transformation of the E. coli strain HB101. Plasma levels of antigen specific IgG antibody were then determined in samples from malaria positive and negative children living in a high malaria transmission region of Cameroon. Results: To improve yield each recombinant phage was scaled up to 10 14 pfu/ml using production strategies previously optimized in our group. This was significantly higher (P<0.001) relative to the 10 8 pfu/ml of the wild type C li nical M ic r o b io logy : O p e n Acces s

The testing of dried blood spots (DBSs) for human immunodeficiency type 1 (HIV-1) proviral DNA by PCR is a technology that has proven to be particularly valuable in diagnosing exposed infants. We implemented this technology for HIV-1 early infant diagnosis (EID) and HIV-1 RNA viral load determination in infants born of HIV-1-seropositive mothers from remote areas in Cameroon. The samples were collected between December 2007 and September 2010. Fourteen thousand seven hundred and sixty-three (14,763) DBS samples from infants born of HIV-positive mothers in 108 sites nationwide were tested for HIV. Of these, 1452 were positive on first PCR analyses (PCR1), giving an overall infection rate of 12.30%. We received only 475 DBS specimen for a second PCR testing (PCR2); out of these, 145 were positive. The median HIV-1 RNA viral load for 169 infant DBS samples tested was 6.85 log copies/ml, with values ranging from 3.37 to 8 log copies/ml. The determination of the viral load on the same DBS as that used for PCR1 allowed us to bypass the PCR2. The viral load values were high and tend to decrease with age but with a weak slope. The high values of viral load among these infants call for early and effective administration of antiretroviral therapy (ART). The findings from this study indicate that the use of DBS provides a powerful tool for perinatal screening programs, improvement on the testing algorithm, and follow-up during treatment, and thus should be scaled up to the entire nation.

Background: Human papillomavirus (HPV) is the leading cause of cervical cancers, causing 270.000 deaths annually worldwide of which 85% occur in developing countries with an increasing risk associated to HIV infection. This study aimed at comparing HPV's positivity and genotype distribution in women according to their HIV status and determinants. Methods: A comparative study was carried out in 2012 at the Chantal BIYA International Reference Centre (CIRCB) among 278 women enrolled consecutively at the General Hospital and the Gynaeco-Obstetric and Paediatric Hospital of the City of Yaoundé. HPV genotyping was performed by real-time PCR, HIV serological screening by serial algorithm, CD4 T cell phenotyping by flow cytometry and HIV viral load by Abbott m2000RT. Statistical analyses were performed using Microsoft Excel 2016 and Graph Pad version 6.0 software; with P < 0.05 considered statistically significant.

Regulatory T (Treg) cells play a key role in dampening excessive immune activation. However, antiretroviral therapy (ART) -naive HIV-1 infection maintains the immune system in a sustained state of activation that could alter both Treg cell surface markers and functions. As Treg cell surface markers are directly linked to their functions the overall objective of this study was to determine how ART-naive HIV infection affects the phenotypic properties of Treg cells. Our data showed that in ART-naive HIV-1 infection, Treg cells are dominated by effector (CD45RA CD27 CCR7 CD62L ) and effector memory (CD45RA CD27 CCR7 CD62L ) cells. In contrast Treg cells from HIV-negative individuals were mainly naive (CD45RA CD27 CCR7 CD62L ) and central memory (CD45RA CD27 CCR7 CD62L ) cells. Whereas effector and effector memory Treg cells showed enhanced expression of CD39 (P < 0·05), CD73 (P < 0·001), HLA-DR and CD38 (P < 0·001); naive and central memory Treg cells showed a significant reduction in the expression of these markers. Overall Treg cell frequencies within total CD4 T cells correlated positively with plasmatic HIV-1 viral load. As increased viral load is associated with augmented CD4 T-cell destruction; this could suggest a resistance of peripheral Treg cells to HIV-1 destruction. Hence the modulation of Treg cell phenotype and frequencies could be considered in designing immunotherapeutic strategies targeting immune system restoration during HIV-1 infection.

Thus targeting protein antigens to DCs using scDEC can be used either alone or in combination with other strategies for effective immunization.

Background: In the context of scaling the viral load in resource limited settings, following HIV infected patient's adults and children with CD4+ T-lymphocyte count still very important in settings where the decentralization of treatment still has some challenges. Effective HIV monitoring in these resource-constrained settings needs affordable and reliable CD4+ T lymphocytes enumeration methods. We investigated the validity of a BD FACSPresto POC which is a dedicated system for enumeration that uses immunofluorescent technologies. In this study, we have assessed the sensitivity, specificity and correlation between most representative flow cytometry instruments present in Cameroon with more than 5000 CD4 T cells tests per year including FACSCalibur, FACSCount, and PIMA POC from Becton-Dickinson and ALERE respectively. Methods: 268 patients aged from 1 to 72 years old were enrolled and included in the study after inform consent. The BD FACSPresto POC CD4+ T cell technology was placed at CIRCB and operated by technician staff. HIV infected patients were from Chantal BIYA international reference Center (CIRCB),

IntroductionRecombinant Newcastle Disease virus (rNDV) vectored vaccines are safe mucosal applicable vaccines with intrinsic immune‐modulatory properties for the induction of efficient immunity. Like all viral vectored vaccines repeated inoculation via mucosal routes invariably results to immunity against viral vaccine vectors. To obviate immunity against viral vaccine vectors and improve the ability of rNDV vectored vaccines in inducing T cell immunity in murine air way we have directed dendritic cell targeted HIV‐1 gag protein (DEC‐Gag) vaccine; for the induction of helper CD4+ T cells to a Recombinant Newcastle disease virus expressing codon optimized HIV‐1 Gag P55 (rNDV‐L‐Gag) vaccine.MethodsWe do so through successive administration of anti‐DEC205‐gagP24 protein plus polyICLC (DEC‐Gag) vaccine and rNDV‐L‐Gag. First strong gag specific helper CD4+ T cells are induced in mice by selected targeting of anti‐DEC205‐gagP24 protein vaccine to dendritic cells (DC) in situ together with polyICLC as adjuvant. This targeting helped T cell immunity develop to a subsequent rNDV‐L‐Gag vaccine and improved both systemic and mucosal gag specific immunity.ResultsThis sequential DEC‐Gag vaccine prime followed by an rNDV‐L‐gag boost results to improved viral vectored immunization in murine airway, including mobilization of protective CD8+ T cells to a pathogenic virus infection site.ConclusionThus, complementary prime boost vaccination, in which prime and boost favor distinct types of T cell immunity, improves viral vectored immunization, including mobilization of protective CD8+T cells to a pathogenic virus infection site such as the murine airway.

BackgroundIn West and Central Africa areas of endemic Loa loa infections overlap with regions of high prevalence of human immunodeficiency virus type 1 (HIV-1) infections. Because individuals in this region are exposed to filarial parasites from birth, most HIV-1 infected individuals invariably also have a history of filarial parasite infection. Since HIV-1 infection both depletes immune system and maintains it in perpetual inflammation, this can hamper Loa loa filarial parasite mediated immune modulation, leading to enhanced loaisis.MethodsIn this study we have assessed in plasma from asymptomatic anti-retroviral (ARV) naïve Loa loa microfilaraemic HIV-1 infected people the filarial antibody responses specific to a filariasis composite antigen consisting of Wbgp29-BmR1-BmM14-WbSXP.The antibody responses specific to the filariasis composite antigen was determined by enzyme linked immunosorbent assay (ELISA) in plasma from ARV naïve Loa loa microfilaraemic HIV-1 infected participants. In addition the filarial antigen specific IgG antibody subclass profiles were also determined for both HIV-1 positive and negative people.ResultsBoth Loa loa microfilaraemic HIV-1 positive and negative individuals showed significantly higher plasma levels of IgG1 (P < 0.0001), IgG2 (P < 0.0001) and IgM (P < 0.0001) relative to amicrofilaraemic participants. A significant increase in IgE (P < 0.0001) was observed exclusively in Loa loa microfilaraemic HIV-1 infected people. In contrast there was a significant reduction in the level of IgG4 (p < 0.0001) and IgG3 (P < 0.0001) in Loa loa microfilaraemic HIV-1 infected individuals.ConclusionsLoa loa microfilaraemia in ARV naïve HIV-1 infected people through differential reduction of plasma levels of filarial antigen specific IgG3, IgG4 and a significant increase in plasma levels of filarial antigen specific IgE could diminish Loa loa mediated immune-regulation. This in effect can result to increase loaisis mediated immunopathology in antiretroviral naive HIV-1 infected people.