Studies on Potency and breadth of HIV-1, HIV-2 and SIV neutralizing antibody responses

Even though the relative contribution of neutralizing antibodies (Nab) to prevent progression to AIDS during HIV-1 infection is still unclear, the induction of broadly NAb directed against HIV-1 through vaccination is considered to represent an important goal for the development of HIV-1 vaccines. Factors contributing to the induction of NAb may include the strength and duration of antigenic stimulation, the preservation of CD4+ T and B cells, the conformation of the HIV-1 envelope glycoprotein complex (Env), and the evolution of Env during infection. To understand these relationships, the experimental model of pathogenic SIV infection in cynomolgus macaques and comparison of HIV-1 and HIV-2 infections in humans were used in this thesis. In the macaque model we studied in parallel the appearance of NAb and evolution of Env. For the preservation of SIV-specific cellular immune responses, early anti-retroviral treatment was provided. The main finding from this study was that the macaques that controlled viral load after treatment discontinuation displayed limited virus population genetic diversity and divergence, and had an early broad NAb response. On the other hand, the macaques with no or transient control of viremia showed greater virus diversity and divergence, and potent NAb response during the early period of infection. We propose that the early phase of viral evolution and the antigenic stimulation contributes to the development of NAb and control of viremia. In humans, HIV-2 is known to be less transmissible and less pathogenic than HIV-1. Therefore, valuable insight can be gained into HIV immunopathogenesis from studies of HIV-2 cohorts with their high proportion of long-term non-progressors. In order to analyze differences in NAb in these infections, we compared, side by side, the breadth and potency of neutralizing activity (NAc) in plasma of HIV-1, HIV-2, and dually HIV-1/2 (HIV-D) infected individuals from Guinea-Bissau against HIV-1 and HIV-2 virus panels. The striking finding was that NAc in HIV-2 plasma against HIV-2 isolates was broader and more potent than NAc in HIV-1 plasma against HIV-1 isolates. Moreover, HIV-D positive individuals had broader and more potent NAc against HIV-2 isolates than HIV-1 isolates, indicating distinct immunogenicity and/or antigenicity of HIV-2 compared to HIV-1. We next analyzed the relative role of IgG and IgA for NAc in HIV-1, HIV-2 and HIV-D plasma. Similarly to the plasma NAc, IgG neutralizing antibodies were found to be more potent in HIV-2 plasma against HIV-2 compared to IgG from HIV-1 plasma against HIV-1. Interestingly, while HIV-2 neutralizing IgA was frequently detected in plasma of HIV-2 infected individuals, HIV-1 neutralizing IgA could rarely be demonstrated in HIV-1 plasma. To study humoral immunity in HIV-1 and HIV-2 infections further, we investigated the role of complement (C’) in antibody-dependent complement-mediated inactivation. Here results showed that the C’ effect on antiviral activity against HIV-2 was more pronounced in HIV-2 plasma than the C’ effect on HIV-1 plasma against HIV-1. Analysis of HIV-D plasma corroborated that the antibody-dependent complement-mediated inactivation was more efficient against HIV-2. This finding suggests that antibody binding to HIV-2 Env facilitates efficient use of C’. In summary, this thesis may provide insights into the nature of broad and potent neutralizing humoral immune responses

A case report of a chronic migraine patient treated with three different anti-CGRP monoclonal antibodies : which parameters better represent the efficacy?

Objective: To report the efficacy of different anti-calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) on headache frequency, intensity, and duration. Background: Blockade of CGRP receptors or neuropeptide with anti-CGRP mAbs have been successfully used for several years for the prevention of chronic and episodic migraine. The response is usually assessed by improvement seen in the number of days with headache per month. However, clinical praxis indicates that sole reliance on the frequency of headaches might be insufficient to interpret the efficacy of these treatments. Methods: Retrospective review of a case with a meticulous headache diary who has tried three different anti-CGRP mAbs for chronic migraine prevention. Results: The patient has been diagnosed with chronic migraine and was first treated with erenumab, followed by fremanezumab and thereafter galcanezumab due to several reasons. In addition to significant improvement in all three parameters analyzed with anti-CGRP mAb treatment, the most important and valuable effect on the patient's quality of life was decreased duration and frequency of headaches. At present, the patient is receiving fremanezumab treatment with an excellent tolerability. Conclusion: There is a clear need for careful follow-up and detailed daily records of headaches showing the frequency, duration, and severity for the evaluation of anti-CGRP mAbs treatment. This study shows the importance of this information in order for medical professionals to make an informed decision regarding the best course of anti-CGRP mAbs treatment in cases of side effects or lack of efficacy

Genetic characterization of human immunodeficiency virus type 1 transmission in the Middle East and North Africa

Background: The HIV-1 spread in the Middle East and North Africa (MENA) has not been previously characterised using the phylogenetic approach. The aim of the current study was to investigate the genetic diversity and domestic transmission of HIV-1 in the MENA. Methods: A total of 2036 HIV-1 sequences available in Genbank and collected in the MENA during 1988–2016 were used together with 715 HIV-1 reference sequences that were retrieved from Genbank based on genetic similarity with the MENA sequences. The REGA and COMET tools were used to determine HIV-1 subtypes and circulating recombinant forms. Maximum Likelihood and Bayesian phylogenetic analyses were used to identify and date HIV-1 transmission clusters. Results: At least 21 HIV-1 subtypes and recombinant forms were prevalent in the MENA. Subtype B was the most common variant (39%), followed by CRF35_AD (19%) and CRF02_AG (14%). The most common genetic region was pol, and 675 partial pol sequences (average of 1005 bp) were eligible for detailed phylogenetic analysis. Fifty-four percent of the MENA sequences formed HIV-1 transmission clusters. Whereas numerous clusters were country-specific, some clusters indicated transmission links between countries for subtypes B, C and CRF02_AG. This was more common in North Africa compared with the Middle East (p < 0.001). Recombinant forms had a larger proportion of clustering compared to pure subtypes (p < 0.001). The largest MENA clusters dated back to 1991 (an Algerian CRF06_cpx cluster of 43 sequences) and 2002 (a Tunisian CRF02_AG cluster of 48 sequences). Conclusions: We found an extensive HIV-1 diversity in the MENA and a high proportion of sequences in transmission clusters. This study highlights the need for preventive measures in the MENA to limit HIV-1 spread in this region

Trends in Antimicrobial Drug Resistance of Streptococcus pneumoniae Isolates at Jordan University Hospital (2000–2018)

Antimicrobial drug resistance (AMR) in pneumococci complicates the treatment of serious pneumococcal infections. Country-specific AMR patterns can help to establish guidelines for empiric therapy. The aim of the current study was to analyze the distribution of AMR among Streptococcus pneumoniae isolates at Jordan University Hospital (JUH) during 2000–2018. Paper-based and electronic clinical data registry records from 2000 to 2018 were retrospectively analyzed to study the AMR among pneumococcal isolates at JUH. Temporal trend analysis was done using two-tailed linear-by-linear test for association. The total number of unique pneumococcal isolates that were identified was 556, of which 544 isolates had antimicrobial susceptibility testing results. The most frequent specimens were eye (n = 117, 21.0%), bloodstream (n = 93, 16.7%) and sputum (n = 81, 14.6%). Invasive infections represented 23.6% of all unique isolates. The overall susceptibility of S. pneumoniae isolates during the study period to different antimicrobials was: 100% to vancomycin, 97.7% to ceftriaxone, 97.1% to cefotaxime, 94.9% to chloramphenicol, 89.7% to penicillin, 83.8% to levofloxacin, 67.7% to clindamycin and 52.1% to erythromycin. The prevalence of multi-drug resistance (MDR) was 8.6% (95% confidence interval: 6.4–11.5%). Trend analysis showed an increase in the prevalence of non-susceptibility to erythromycin, clindamycin and levofloxacin (p < 0.001). MDR prevalence increased from 1.6% in the first quarter to 14.6% in the fourth quarter (p < 0.001). The incidence of invasive infections declined over the study period (p < 0.001). The increase in the prevalence of AMR and MDR among pneumococcal isolates in Jordan demands judicious use of antimicrobials and regular surveillance of resistance

Automated image-based assay for evaluation of HIV neutralization and cell-to-cell fusion inhibition

Background: Standardized techniques to detect HIV-neutralizing antibody responses are of great importance in the search for an HIV vaccine. Methods: Here, we present a high-throughput, high-content automated plaque reduction (APR) assay based on automated microscopy and image analysis that allows evaluation of neutralization and inhibition of cell-cell fusion within the same assay. Neutralization of virus particles is measured as a reduction in the number of fluorescent plaques, and inhibition of cell-cell fusion as a reduction in plaque area. Results: We found neutralization strength to be a significant factor in the ability of virus to form syncytia. Further, we introduce the inhibitory concentration of plaque area reduction (ICpar) as an additional measure of antiviral activity, i.e. fusion inhibition. Conclusions: We present an automated image based high-throughput, high-content HIV plaque reduction assay. This allows, for the first time, simultaneous evaluation of neutralization and inhibition of cell-cell fusion within the same assay, by quantifying the reduction in number of plaques and mean plaque area, respectively. Inhibition of cell-to-cell fusion requires higher quantities of inhibitory reagent than inhibition of virus neutralization

An update on hepatitis C virus genotype distribution in Jordan: a 12-year retrospective study from a tertiary care teaching hospital in Amman

Background: Nucleic acid hybridization (NAH) of hepatitis C virus (HCV) is a practical and reliable tool for virus genotyping. Genotype assignment is an important factor in the prediction of treatment success in chronic hepatitis C patients. The aim of this study was to determine the genotype distribution among HCV clinical isolates in Jordan between 2007 and 2018. Methods: Electronic and paper-based clinical data registry records from 2007 to 2018 at the Jordan University Hospital (JUH) were retrospectively examined for individuals with HCV genotype, HCV viral load, and alanine aminotransferase (ALT) testing results. Genotype determination was based on NAH technique using the HCV 5′ untranslated region (5′ UTR) with 386 requests available from 342 unique individuals. Results: A total of 263 out of 342 unique individuals (76.9%) had genotyping results available for final analysis with 259 individuals each having a single genotyping result. The most common HCV genotypes in the study were: genotype 4 (n = 142, 54.0%), genotype 1 (n = 87, 33.1%), genotype 3 (n = 16, 6.1%), genotype 2 (n = 9, 3.4%), other undetermined genotypes (n = 5, 1.9%) and mixed infections (n = 4, 1.5%). Sub-genotyping results were available for 46 individuals as follows: sub-genotype 4c/d (n = 13, 28.3%), sub-genotype 1a (n = 11, 23.9%), sub-genotype 1b (n = 10, 21.7%), sub-genotype 4a (n = 8, 17.4%), sub-genotype 3a (n = 2, 4.3%), sub-genotypes 2a/c and 4 h (n = 1, 2.2% for both). Individuals infected with genotype 1 showed higher viral load when compared to those infected with genotype 4 (p = 0.048, t-test). Younger HCV-infected individuals (< 52 years) had higher ALT levels compared to older individuals (p = 0.036, t-test). Self-reported risk factors for HCV acquisition included: history of previous surgery, invasive dental procedures, and blood transfusion, delivery at home, circumcision at home and wet cupping therapy (hijama). Conclusions: High genetic diversity of HCV was found in Jordan, with genotypes 4 and 1 as the most prevalent genotypes co-circulating in the country. Potential impact of virus genotype on disease markers (viral load, ALT) was detected and needs further assessment. The study can be helpful to plan for future prevention and management of HCV infection in Jordan

Dental students’ awareness and attitudes toward HPV-related oral cancer: a cross sectional study at the University of Jordan

BackgroundThe incidence of human papilloma virus (HPV)-related oral cancer has recently increased worldwide. The role of dentists is of prime importance in the early detection of oral cancer which would result in a favourable outcome for the patients. The aim of the current study was to assess the knowledge, awareness and attitudes of dental students, interns and postgraduate maxillofacial residents at the University of Jordan (UJ) to different aspects of oral cancer, particularly those related to HPV.MethodsA paper-based survey was conducted at UJ among all pre-clinical dental students (pre-clinical group), clinical dental students, interns and postgraduate maxillofacial residents (clinical group). The survey included five sections comprising 29 items. The sections included questions investigating oral cancer knowledge, oral cancer screening, HPV knowledge and the ability to discuss personal topics with patients.ResultsA total of 376 respondents out of 1052 potential participants completed at least one item of the survey (study coverage of 35.7%). Among the study participants, the pre-clinical group represented 41.2% (n = 155) and the clinical group represented 58.8% (n = 221). The majority of participants in the clinical group showed better knowledge on oral cancer potential anatomic sites, clinical presentation and possible risk factors compared to the pre-clinical group. Most participants in the clinical group (n = 195, 88.2%) correctly identified HPV as a risk factor for oral cancer development. The majority of participants in the clinical group displayed suitable attitude towards oral cancer screening despite their desire for a reliable screening device and additional training in oral cancer screening. A number of limitations in basic knowledge about HPV was noticed among participants in the clinical group particularly related to unawareness of the vaccine availability. The majority of participants in the clinical group displayed hesitancy in discussing personal topics with the patients, including the history of previous sexually transmitted infections and sexual abuse.ConclusionsGaps in knowledge regarding HPV-related oral cancer has been detected which necessitate intervention measures including curricular changes, training workshops and awareness campaigns

Cross-Reactive Antibodies With the Capacity to Mediate HIV-1 Envelope Glycoprotein-Targeted Antibody-Dependent Cellular Cytotoxicity Identified in HIV-2-Infected Individuals

Disease progression of human immunodeficiency virus type 1 (HIV-1) is delayed by HIV type 2 (HIV-2) in individuals with dual HIV-1/HIV-2 infection. The protective mechanisms, however, are still to be revealed. In the current study we examined type-specific and cross-reactive antibody-dependent cellular cytotoxicity (ADCC) in HIV-1 and HIV-2 monoinfection or dual infection. Of note, intertype cross-reactive antibodies that mediated HIV-1 envelope glycoprotein (Env)-targeted ADCC were frequently identified in HIV-2-infected individuals. Furthermore, the magnitude of HIV-1 cross-reactive ADCC activity during HIV-2 infections depended on the HIV-1 Env origin and was associated with the duration of infection. These results suggest that preexisting antibodies against HIV-2, which mediate intertype ADCC, might contribute to control of HIV-1 during dual infection