Human antiviral B cell responses: Emerging lessons from hepatitis B and COVID-19

Humoral immunity is a critical component of the coordinated response required to resolve viral infections and mediate protection following pathogen clearance or vaccination. A better understanding of factors shaping the memory B cell response will allow tailored development of efficient preventative vaccines against emerging acute viral infections, therapeutic vaccines, and immunotherapies for chronic viral infections. Here, we use recent data obtained by profiling antigen-specific B cell responses in hepatitis B as a framework to explore lessons that can be learnt from different viral infections about the diverse influences on humoral immunity. Hepatitis B provides a paradigm where successful B cell responses in resolved or vaccinated individuals can be contrasted to the failed response in chronic infection, while also exemplifying the degree to which B cell responses within infected individuals can differ to two antigens from the same virus. Drawing on studies in other human and murine infections, including emerging data from COVID-19, we consider the influence of antigen quantity and structure on the quality of the B cell response, the role of differential CD4 help, the importance of germinal center vs extrafollicular responses and the emerging concept that responses residing in non-lymphoid organs can participate in B cell memory

Restoring, releasing or replacing adaptive immunity in chronic hepatitis B

Multiple new therapeutic approaches are currently being developed to achieve sustained, off-treatment suppression of HBV, a persistent hepatotropic infection that kills ~2,000 people a day. A fundamental therapeutic goal is the restoration of robust HBV-specific adaptive immune responses that are able to maintain prolonged immunosurveillance of residual infection. Here, we provide insight into key components of successful T cell and B cell responses to HBV, discussing the importance of different specificities and effector functions, local intrahepatic immunity and pathogenic potential. We focus on the parallels and interactions between T cell and B cell responses, highlighting emerging areas for future investigation. We review the potential for different immunotherapies in development to restore or release endogenous adaptive immunity by direct or indirect approaches, including limitations and risks. Finally, we consider an alternative HBV treatment strategy of replacing failed endogenous immunity with infusions of highly targeted T cells or antibodies

Anomalous centrality variation of minijet angular correlations in Au-Au collisions at 62 and 200 GeV from STAR

We have measured 2D autocorrelations for all charged hadrons in STAR with $p_{t}$ $>$ 0.15 GeV/c and $| \eta |$ $<$ 1 from Au+Au collisions at 62 and 200 GeV. The correlation structure is dominated by a peak centered at zero relative opening angles on $\eta$ and $\phi$ which we hypothesize is caused by minimum-bias jets (minijets). We observe a large excess of minijet correlations in more-central Au-Au collisions relative to binary-collision scaling (more correlated pairs than expected from surface emission or even volume emission). We also observe a sudden increase of the minijet peak amplitude and $\eta$ width relative to binary-collision scaling of scattered partons which occurs at an energy-dependent centrality point. There is a possible scaling of the transition point with transverse particle density.Comment: Quark Matter 2008 proceedings, submitted to Journal of Physics G. v2: added STAR Collaboration to author lis

K* production in Cu+Cu and Au+Au collisions at sqrt(s_{NN}) = 62.4 GeV and 200 GeV in STAR

We report the measurements of $p_T$ spectra of $K^*$ up to intermediate $p_T$ region in mid-rapidity through its hadronic decay channel using the STAR detector in Au+Au and Cu+Cu collisions at $\sqrt{s_{\mathrm{NN}}}$= 62.4 GeV and 200 GeV. Particle ratios such as $K^{*}/K$ and $K^{*}/\phi$ is used to understand the rescattering and regeneration effect on $K^{*}$ production in the hadronic medium. The $K^*$ $v_{2}$ measurement using a high statistics Au+Au 200 GeV dataset and nuclear modification factor measurement supports the quark coalescence model of particle production in the intermediate $p_T$ range.Comment: 5 page

STAR's measurement of Long-range forward-backward multiplicity correlations as the signature of "dense partonic matter" in the Heavy Ion collisions at sNN=\sqrt{s_{NN}}=200 GeV.}

Forward-backward multiplicity correlations have been measured with the STAR detector for Au+Au, Cu+Cu and {\it p+p} collisions at $\sqrt{s_{NN}}$ = 200 GeV. A strong, long-range correlation is observed for central heavy ion collisions that vanishes in semi-peripheral events and {\it pp} collisions. There is no apparent scaling of correlation strength with the number of participants involved in the collision. Both the Dual Parton Model and the Color Glass condensate indicate that the long range correlations are due to multiple parton interactions. This suggests that the dense partonic matter might have been created in mid-central and central Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV.Comment: 4 pages, 3 figures,presented at the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur, India, February 4-10, 200

Υ\Upsilon production in p+p and Au+Au collisions in STAR

The study of quarkonium production in relativistic heavy ion collisions provides insight into the properties of the produced medium. The lattice studies show a sequential suppression of quarkonia states when compared to normal nuclear matter; which further affirms that a full spectroscopy including bottomonium can provide us a better thermometer for the matter produced under extreme conditions in relativistic heavy ion collisions. With the completion of the STAR Electromagnetic Calorimeter and with the increased luminosity provided by RHIC in Run 6 and 7, the study of $\Upsilon$ production via the di-electron channel becomes possible. We present the results on $\Upsilon$ measurements in p+p collisions (from Run 6) along with the first results from Au+Au collisions (in Run 7) at $\sqrt{s_{\rm{NN}}} = 200$ GeV from the STAR experiment.Comment: 4 pages and 2 figures, Oral Presentation at QM2008 February 4-10, 2008: Jaipur India. submitted to Journal Of Physics-G:Nuclear and Particle Physic

Direct photon-charged hadron azimuthal correlations

Azimuthal correlations of direct photons at high transverse energy (8 $<$ E$_T$ $<$ 16 GeV) with away-side hadrons of transverse momentum (3 $<$ p$_T$ $<$ 6 GeV/c) have been measured over a broad range of centrality for $Au+Au$ collisions and $p+p$ collisions at $\sqrt{s_{NN}}$ = 200 GeV. The presented results are the first measurements at RHIC for $\gamma$-hadron azimuthal correlations in $Au+Au$ collisions.Comment: 4 pages, 3 figure

Baryon to Meson Ratios on the Near and Away-Side of Jets and their Centrality Dependence at STAR

We measure relative abundances of $K_{S}^{0}$, $\Lambda$ and $\bar{\Lambda}$ in near-side and away-side cones correlated with triggered high-$p_{T}$ particles in $^{197}$Au + $^{197}$Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The centrality dependence of identified particles in the triggered particle cones is also presented. Particle yields and ratios are extracted on the near-side and away-side of the trigger particle. The associate-particle ratios are studied as a function of the angle relative to the trigger particle azimuth $\Delta\phi$. Such studies should help elucidate the origin of the modifications in the jet like correlations observed in Au+Au collisions relative to p+p collisions. And these studies also will help understand the variation of local parton densities at the away side. We discuss how these measurements might be related to several scenarios for interactions of fast partons with the medium created in Au+Au collision.Comment: 6 pages, 4 figures, Proceedings for SQM 2007 Talk, Levoca, Slovakia, June 24-29, 200

Strangeness and bulk freeze-out properties at RHIC

Identified charged kaon, pion, and proton spectra and ratios from sqrt(s_NN) = 200 and 62.4 GeV Cu+Cu collisions are studied with a hydro-motivated blast-wave and a statistical model framework in order to explore the strangeness production at RHIC and characterize the bulk freeze-out properties of the created system. The spectra are measured at mid-rapidity |y|<0.1 over the transverse momentum range of 0.25 < p_T < 1.2 GeV/c with particle identification derived from the ionization energy loss in the STAR Time Projection Chamber. The multi-dimensional systematic study of pi(+/-), K(+/-), p and pbar production in Cu+Cu, Au+Au, d+Au and p+p collisions is used to discuss the energy, system size and inferred energy density dependence of freeze-out parameters and strangeness production. The new data from Cu+Cu collisions bridge the gap between the smaller d+Au and larger Au+Au systems, allowing a detailed study of the onset of strangeness equilibration at RHIC.Comment: 6 pages, 5 figures, proceedings to Strangeness in Quark Matter 200