Antibody response against selected epitopes in the HIV-1 envelope gp41 ectodomain contributes to reduce viral burden in HIV-1 infected patients

The ectodomain of gp41 is the target of potent binding and neutralizing antibodies (NAbs) and is being explored in new strategies for antibody-based HIV vaccines. Previous studies have suggested that the W164A-3S (3S) and EC26-2A4 (EC26) peptides located in the gp41 ectodomain may be potential HIV vaccine candidates. We assessed 3S- and EC26-specific binding antibody responses and related neutralizing activity in a large panel of chronic HIV-1-infected Portuguese individuals on ART. A similar proportion of participants had antibodies binding to 3S (9.6%) and EC26 (9.9%) peptides but the level of reactivity against 3S was significantly higher compared to EC26, except in the rare patients with double peptide reactivity. The higher antigenicity of 3S was unrelated with disease stage, as assessed by CD4⁺ T cell counts, but it was directly related with plasma viral load. Most patients that were tested (89.9%, N = 268) showed tier 1 neutralizing activity, the potency being inversely associated with plasma viral load. In the subset of patients that were tested for neutralization of tier 2 isolates, neutralization breadth was inversely correlated with plasma viral load and directly correlated with CD4⁺ T cell counts. These results are consistent with a role for neutralizing antibodies in controlling viral replication and preventing the decline of CD4⁺ T lymphocytes. Importantly, in patients with 3S-specific antibodies, neutralizing titers were inversely correlated with viral RNA levels and proviral DNA levels. Moreover, patients with 3S and/or EC26-specific antibodies showed a 1.9-fold higher tier 2 neutralization score than patients without antibodies suggesting that 3S and/or EC26-specific antibodies contribute to neutralization breadth and potency in HIV-1 infected patients. Overall, these results suggest that antibodies targeting the S3 and EC26 epitopes may contribute to reduce viral burden and provide further support for the inclusion of 3S and EC26 epitopes in HIV-1 vaccine candidates.

Differential expansion of circulating human MDSC subsets in patients with cancer, infection and inflammation

Background

Myeloid-derived suppressor cells (MDSC) are a functional myeloid cell subset that includes myeloid cells with immune suppressive properties. The presence of MDSC has been reported in the peripheral blood of patients with several malignant and non-malignant diseases. So far, direct comparison of MDSC across different diseases and Centers is hindered by technical pitfalls and a lack of standardized methodology. To overcome this issue, we formed a network through the COST Action Mye-EUNITER (www.mye-euniter.eu) with the goal to standardize and facilitate the comparative analysis of human circulating MDSC in cancer, inflammation and infection. In this manuscript, we present the results of the multicenter study Mye-EUNITER MDSC Monitoring Initiative, that involved 13 laboratories and compared circulating MDSC subsets across multiple diseases, using a common protocol for the isolation, identification and characterization of these cells.

Methods

We developed, tested, executed and optimized a standard operating procedure for the isolation and immunophenotyping of MDSC using blood from healthy donors. We applied this procedure to the blood of almost 400 patients and controls with different solid tumors and non-malignant diseases. The latter included viral infections such as HIV and hepatitis B virus, but also psoriasis and cardiovascular disorders.

Results

We observed that the frequency of MDSC in healthy donors varied substantially between centers and was influenced by technical aspects such as the anticoagulant and separation method used. Expansion of polymorphonuclear (PMN)-MDSC exceeded the expansion of monocytic MDSC (M-MDSC) in five out of six solid tumors. PMN-MDSC expansion was more pronounced in cancer compared with infection and inflammation. Programmed death-ligand 1 was primarily expressed in M-MDSC and e-MDSC and was not upregulated as a consequence of disease. LOX-1 expression was confined to PMN-MDSC.

Conclusions

This study provides improved technical protocols and workflows for the multi-center analysis of circulating human MDSC subsets. Application of these workflows revealed a predominant expansion of PMN-MDSC in solid tumors that exceeds expansion in chronic infection and inflammation.

Early ART in Acute HIV-1 Infection: Impact on the B-Cell Compartment

HIV-1 infection induces B cell defects, not fully recovered upon antiretroviral therapy (ART). Acute infection and the early start of ART provide unique settings to address the impact of HIV on the B cell compartment. We took advantage of a cohort of 21 seroconverters, grouped according to the presence of severe manifestations likely mediated by antibodies or immune complexes, such as Guillain-Barré syndrome and autoimmune thrombocytopenic purpura, with a follow-up of 8 weeks upon effective ART. We combined B and T cell phenotyping with serum immunoglobulin level measurement and quantification of sj-KRECs and ΔB to estimate bone marrow output and peripheral proliferative history of B cells, respectively. We observed marked B cell disturbances, notably a significant expansion of cells expressing low levels of CD21, in parallel with markers of both impaired bone marrow output and increased peripheral B cell proliferation. This B cell dysregulation is likely to contribute to the severe immune-mediated conditions, as attested by the higher serum IgG and the reduced levels of sj-KRECs with increased ΔB in these individuals as compared to those patients with mild disease. Nevertheless, upon starting ART, the dynamic of B cell recovery was not distinct in the two groups, featuring both persistent alterations by week 8. Overall, we showed for the first time that acute HIV-1 infection is associated with decreased bone marrow B cell output assessed by sj-KRECs. Our study emphasizes the need to intervene in both bone marrow and peripheral responses to facilitate B cell recovery during acute HIV-1 infection.

Kaposi Sarcoma of the eyelid as an initial manifestation of AIDS

Kaposi sarcoma (KS) is a multifocal systemic disease that originates in the vascular endothelium related to Human Herpes Virus 8 (HHV-8). In the early 1980s the first series of cases of disseminated Kaposi Sarcoma in HIV infected patients were reported. However, with the advent of highly active antiretroviral therapy (HAART) since 1997, these cases are less frequently observed by clinicians. We report the case of a 40-year-old woman, presenting with two asymptomatic purpuric nodules localized in the superior and inferior left eyelids, occluding the palpebral fissure, which were present for 4 months prior to presentation. The eyelid nodules were determined to represent KS, but there were no additional cutaneous lesions. Pulmonary and gastric KS involvement was documented. Antiretroviral therapy was initiated along with pegylated liposomal doxorubicin. The nodules gradually disappeared and her immune status eventually improved. Ocular and periorbital involvement of KS associated with HIV-1 infection as the initial clinical manifestations is a rare advent. This case is important as it illustrates that disseminated KS was not to be predicted by the number or the extension of cutaneous lesions.

A case of imported neurocysticercosis in Portugal

Neurocysticercosis (NCC) is the most common cause of acquired epilepsy in resource-poor countries. We report the case of a 24-year-old woman born and residing in Guinea-Bissau, who was transferred to Portugal two months after the onset of a possible meningitis (fever, headache, seizures, and coma) that did not respond to antibiotic treatment. The diagnosis of NCC was confirmed by MR imaging, which showed multiple lesions compatible with cysticercus, and by polymerase chain reaction (PCR) of the cerebrospinal fluid. After 28 days on albendazole and dexamethasone without improvement, she was started on praziquantel, which she completed in six weeks with progressive recovery.

Acute Q fever in Portugal. Epidemiological and clinical features of 32 hospitalized patients

INTRODUCTION

Q fever is a worldwide zoonosis caused by Coxiella burnetii. The main characteristic of acute Q fever is its clinical polymorphism, usually presenting as a febrile illness with varying degrees of hepatitis and/or pneumonia. Q fever is endemic in Portugal, and it is an obligatory notifiable disease since 1999. However, its epidemiological and clinical characteristics are still incompletely described.

METHODS

We performed a retrospective study of 32 cases admitted in the Infectious Diseases Department, Santa Maria's University Hospital, from January 2001 to December 2010, in whom acute Q fever was diagnosed by the presence of antibodies to phase II Coxiella burnetii antigens associated with a compatible clinical syndrome.

RESULTS

Out of the 32 cases recorded, 29 (91%) were male, with a male:female ratio of 9.7:1. Individuals at productive age were mainly affected (88%, n=28, with ages between 25 and 64 years). Clinically, the most common manifestation of acute Q fever was hepatic involvement (84%, n=27), which occurred isolated in 53% (n=17) of the cases. Hepatitis was more severe, presenting with higher values of liver function tests, in patients presenting both pulmonary and hepatic involvement. Additionally, we report one case of myocarditis and another one with neurological involvement. Empiric but appropriate antibiotic therapy was given in 66% (n=21) of the cases. There was a complete recovery in 94% (n=30) of the patients, and one death. We confirmed the sub-notification of this disease in Portugal, with only 47% (n=15) of the cases notified.

CONCLUSION

In Portugal further studies are needed to confirm our results. From the 32 cases studied, acute Q fever presented more frequently as a febrile disease with hepatic involvement affecting mainly young male individuals. Furthermore, acute Q fever is clearly underdiagnosed and underreported in Portugal, which suggests that an increased awareness of the disease is needed, together with a broader use of serological testing.

Cellular immune responses to Mycobacterium tuberculosis in a patient with Takayasu's arteritis

INTRODUCTION

Takayasu's arteritis (TA) is a disease of unknown aetiology, characterized histologically by an inflammatory cell infiltrate that affects all layers of the arterial wall. Its association with tuberculosis (TB) was described 50 years ago, based on the presence of Langhan's giant cells and granulomas similar to those found in tuberculous lesions. The presence of TB in patients with TA well as been reported in several studies as well as a positive tuberculous response, but these associations could be fortuitous in countries where TB is endemic. Recent studies have shown that patients with TA have a heightened humoral response to mycobacterial antigens including the 65 kDa fraction, a heat shock protein (HSP) that has also been found to be expressed in the arterial wall of patients with TA. The purpose of this study was to determine lymphoproliferative response and interferon-gamma (IFN-gamma) production by peripheral blood mononuclear cells (PBMC) stimulated by live Mycobacterium tuberculosis (Mtb) H37Rv and a panel of mycobacterial antigens, in the hope of contributing to a better understanding of the cellular immune responses to Tuberculosis in Takayasu's arteritis.

MATERIAL AND METHODS

Standard lymphoproliferation tests and IFN-gamma determination (ELISA) were performed in a 47-year old black man who fulfilled criteria for TA and 10 healthy controls, BCG vaccinated, Mantoux positive. The following were used: Mtb H37Rv, Purified Protein Derivative (PPD), purified 30 kDa, recombinant M. bovis BCG 10 kDa, 38 kDa, 65 kDa, 70 kDa, Short Term-Culture Filtrate Proteins (ST-CFP), Mid Term-Culture Filtrate Proteins (MT-CFP) obtained from H37Rv and phytohemaglutinin (PHA) as mitogen for positive control.

RESULTS

PBMC from the patient with TA when compared to the mean values of the 10 healthy donors showed decreased proliferation in response to all antigens, with the exception of 65 kDa. The TA patient showed a similar pattern of IFN-gamma production to that obtained with control donors, with the exception of higher IFN-gamma production in response to ST-CFP and MT-CFP.

CONCLUSIONS

We have shown reactivity of peripheral lymphocytes to HSP 65 kDa and a trend towards higher production of IFN-gamma in response to ST-CFP and MT-CFP in a patient with TA. These facts, together with the already established heightened humoral response, strengthens the association between TB and TA. However, HSP 65 kDa is not specific to TB and we conclude that similar studies using lymphocytes obtained from the arterial wall of TA patients may help to clarify the role of mycobacterial infection in Takayasu's arteritis.

[Cellular immune response to mycobacterial antigens]

The authors studied the immunological response before and after beginning anti-tuberculous therapy, of a previously health, HIV negative, 22 year old black male, from the Republic of Cape Verde. The patient had multiple vertebral bony lesions associated to subcutaneous abscesses. As immunological markers of antigen recognition, we measured blastogenic and cytotoxic responses and gamma-IFN secretion towards 30 kD, 65 kD, filtrate proteins of M. tuberculosis, M. tuberculosis (H37Rv) and PPD cultures. To characterise the role of cytokines during infection, expression of mRNA for gamma-IFN, IL-4 and IL-10 was also analysed. A slight increase of lymphocyte proliferation and gamma-IFN production was seen in response to purified protein derivative (PPD) and short term culture filtrate proteins (ST-CFP), after one month of therapy. More significant, was the increase in M. tuberculosis and PPD-specific cytolytic T lymphocyte response after one one month of treatment. After 6 months of treatment, blastogenic and cytotoxic responses and gamma-IFN production were considerably higher toward the antigen panel. The CD4/CD8 ratio increased from 0.7 to 1.4 after treatment. We observed that ST-CFP and MT-CFP induced increasingly higher lymphoproliferation and gamma-IFN production, confirming their role in the protective immune responses to M. tuberculosis. The reduced immune responses in the peripheral blood of this patient probably reflect a high activity in the local sites of infection. This case of disseminated tuberculosis infection maybe related to nutritional or social factors or may represent an example of reduced in ate resistance against tuberculosis infection.

[The effect of technopathologically limited stress factors on the fertility of cattle]

The influence of purulent claw-diseases on the development of uterus infections, its involution and ovary dysfunctions (acyclia, cysts) was examined. It was shown that A. pyogenes, Ps. aeruginosa, Fus. necrophorum and other microorganisms involved in these lesions are potential sources for the infections of the uterus. In comparison with the controls the frequency of endometritis was twice in the group with claw-problems. Similar differences existed in the involution-time of the uterus or its atonia, acyclia and the development of ovarian cysts (p less than 0.01). The Index of insemination was elevated by about 65%.