Objectives: Convalescent plasma (CP) as a passive source of neutralizing antibodies and immunomodulators is a century-old therapeutic option used for the management of viral diseases. We investigated its effectiveness for the treatment of COVID-19. Design: Open-label, parallel-arm, phase II, multicentre, randomized controlled trial. Setting: Thirty-nine public and private hospitals across India. Participants: Hospitalized, moderately ill confirmed COVID-19 patients (PaO2/FiO2: 200-300 or respiratory rate > 24/min and SpO2 ≤ 93% on room air). Intervention: Participants were randomized to either control (best standard of care (BSC)) or intervention (CP + BSC) arm. Two doses of 200 mL CP was transfused 24 hours apart in the intervention arm. Main Outcome Measure: Composite of progression to severe disease (PaO2/FiO2<100) or all-cause mortality at 28 days post-enrolment. Results: Between 22 nd April to 14 th July 2020, 464 participants were enrolled; 235 and 229 in intervention and control arm, respectively. Composite primary outcome was achieved in 44 (18.7%) participants in the intervention arm and 41 (17.9%) in the control arm [aOR: 1.09; 95% CI: 0.67, 1.77]. Mortality was documented in 34 (13.6%) and 31 (14.6%) participants in intervention and control arm, respectively [aOR) 1.06 95% CI: -0.61 to 1.83]. Interpretation: CP was not associated with reduction in mortality or progression to severe COVID-19. This trial has high generalizability and approximates real-life setting of CP therapy in settings with limited laboratory capacity. A priori measurement of neutralizing antibody titres in donors and participants may further clarify the role of CP in management of COVID-19.
The HIV-1 envelope (Env) is a glycoprotein consisting of a trimer of heterodimers containing gp120 and gp41 subunits that mediates virus entry and is a major target of broadly neutralizing antibodies (bnAbs) developed during infection in some individuals. The engagement of the HIV-1 gp120 glycoprotein to the host CD4 protein triggers conformational changes in gp120 that allow its binding to co-receptors and is necessary for virus entry to establish infection. Native-like HIV-1 Env immunogens representing distinct clades have been proposed to improve immunogenicity. In the present study, we examined the basis of resistance of an HIV-1 B/C recombinant Env (LT5.J4b12C) to non-neutralizing antibodies targeting CD4-induced Env epitopes in the presence of soluble CD4 (sCD4). Using native polyacrylamide gel shift assay and negative-stain EM, we found that the prefusion conformational state of LT5.J4b12C trimeric Env was largely unaffected in the presence of excess sCD4 with most Env trimers appearing to be in a ligand-free state. This resistance to CD4-induced conformational changes was associated with a lower affinity for CD4. Moreover, the LT5.J4b12C trimeric Env preferentially bound to the neutralizing antibodies compared with non-neutralizing antibodies. Taken together, we report on an HIV-1 B/C recombinant, native-like trimeric Env protein that is highly resistant to CD4-induced conformational changes but displays epitopes recognized by a diverse array of bnAbs. Such features make this B/C recombinant trimeric Env a useful addition to the pool of other recently identified native-like HIV-1 Env trimers suitable for use as antigenic bait for bnAb isolation, structural studies, and use as potential immunogens.
ObjectiveLarge data on the clinical characteristics and outcome of COVID-19 in the Indian population are scarce. We analysed the factors associated with mortality in a cohort of moderately and severely ill patients with COVID-19 enrolled in a randomised trial on convalescent plasma.DesignSecondary analysis of data from a Phase II, Open Label, Randomized Controlled Trial to Assess the Safety and Efficacy of Convalescent Plasma to Limit COVID-19 Associated Complications in Moderate Disease.Setting39 public and private hospitals across India during the study period from 22 April to 14 July 2020.ParticipantsOf the 464 patients recruited, two were lost to follow-up, nine withdrew consent and two patients did not receive the intervention after randomisation. The cohort of 451 participants with known outcome at 28 days was analysed.Primary outcome measureFactors associated with all-cause mortality at 28 days after enrolment.ResultsThe mean (SD) age was 51±12.4 years; 76.7% were males. Admission Sequential Organ Failure Assessment score was 2.4±1.1. Non-invasive ventilation, invasive ventilation and vasopressor therapy were required in 98.9%, 8.4% and 4.0%, respectively. The 28-day mortality was 14.4%. Median time from symptom onset to hospital admission was similar in survivors (4 days; IQR 3–7) and non-survivors (4 days; IQR 3–6). Patients with two or more comorbidities had 2.25 (95% CI 1.18 to 4.29, p=0.014) times risk of death. When compared with survivors, admission interleukin-6 levels were higher (p<0.001) in non-survivors and increased further on day 3. On multivariable Fine and Gray model, severity of illness (subdistribution HR 1.22, 95% CI 1.11 to 1.35, p<0.001), PaO2/FiO2 ratio <100 (3.47, 1.64–7.37, p=0.001), neutrophil lymphocyte ratio >10 (9.97, 3.65–27.13, p<0.001), D-dimer >1.0 mg/L (2.50, 1.14–5.48, p=0.022), ferritin ≥500 ng/mL (2.67, 1.44–4.96, p=0.002) and lactate dehydrogenase ≥450 IU/L (2.96, 1.60–5.45, p=0.001) were significantly associated with death.ConclusionIn this cohort of moderately and severely ill patients with COVID-19, severity of illness, underlying comorbidities and elevated levels of inflammatory markers were significantly associated with death.Trial registration numberCTRI/2020/04/024775.
It is essential to examine the longevity of the defensive immune response engendered by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. We examined the SARS-CoV-2-specific antibody responses and ex vivo memory B-cell subsets in seven groups of individuals with COVID-19 classified based on days since reverse-transcription polymerase chain reaction confirmation of SARS-CoV-2 infection. Our data showed that the levels of IgG and neutralizing antibodies started increasing from days 15 to 30 to days 61 to 90, and plateaued thereafter. The frequencies of naive B cells and atypical memory B cells decreased from days 15 to 30 to days 61 to 90, and plateaued thereafter. In contrast, the frequencies of immature B cells, classical memory B cells, activated memory B cells, and plasma cells increased from days 15 to 30 to days 61 to 90, and plateaued thereafter. Patients with severe COVID-19 exhibited increased frequencies of naive cells, atypical memory B cells, and activated memory B cells, and lower frequencies of immature B cells, central memory B cells, and plasma cells when compared with patients with mild COVID-19. Therefore, our data suggest modifications in memory B-cell subset frequencies and persistence of humoral immunity in convalescent individuals with COVID-19.
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