Human CD4-binding site antibody elicited by polyvalent DNA prime-protein boost vaccine neutralizes cross-clade tier-2-HIV strains.

The vaccine elicitation of HIV tier-2-neutralization antibodies has been a challenge. Here, we report the isolation and characterization of a CD4-binding site (CD4bs) specific monoclonal antibody, HmAb64, from a human volunteer immunized with a polyvalent DNA prime-protein boost HIV vaccine. HmAb64 is derived from heavy chain variable germline gene IGHV1-18 and light chain germline gene IGKV1-39. It has a third heavy chain complementarity-determining region (CDR H3) of 15 amino acids. On a cross-clade panel of 208 HIV-1 pseudo-virus strains, HmAb64 neutralized 20 (10%), including tier-2 strains from clades B, BC, C, and G. The cryo-EM structure of the antigen-binding fragment of HmAb64 in complex with a CNE40 SOSIP trimer revealed details of its recognition; HmAb64 uses both heavy and light CDR3s to recognize the CD4-binding loop, a critical component of the CD4bs. This study demonstrates that a gp120-based vaccine can elicit antibodies capable of tier 2-HIV neutralization.

Human CD4-Binding Site Antibody Elicited by Polyvalent DNA Prime-Protein Boost Vaccine Neutralizes Cross-Clade Tier-2-HIV Strains.

The vaccine elicitation of HIV-neutralizing antibodies with tier-2-neutralization breadth has been a challenge. Here, we report the isolation and characteristics of a CD4-binding site specific monoclonal antibody, HmAb64, from a human volunteer immunized with a polyvalent gp120 DNA prime-protein boost vaccine. HmAb64 derived from heavy chain variable germline gene IGHV1-18, light chain germline gene IGKV1-39, and had a 3rd heavy chain complementarity determining region (CDR H3) of 15 amino acids. On a cross-clade panel of 208 HIV-1 pseudo-virus strains, HmAb64 neutralized 21 (10%), including tier-2 neutralization resistant strains from clades B, BC, C, and G. The cryo-EM structure of the antigen-binding fragment of HmAb64 bound to a conformation between prefusion closed and occluded open forms of envelope trimer, using both heavy and light CDR3s to recognize the CD4-binding loop, a critical component of the CD4-binding site. A gp120 subunit-based vaccine can thus elicit an antibody capable of tier 2-HIV neutralization.

Diagnostic and Prognostic Value of Aspartate Transaminase-to-platelet Ratio Index, Gamma-glutamyl Transpeptidase-to-platelet Ratio, and Fibrosis-4 for Compensated Hepatitis B-related Liver Cirrhosis.

The aim of this study was to investigate a serodiagnostic model as a substitute for liver stiffness measurement (LSM) for diagnosing compensated liver cirrhosis (LC). This retrospective study included 150 patients with compensated hepatitis B-related LC and 153 with chronic Hepatitis B virus (HBV) infection. It was conducted from May 2017 to June 2022 at Qinghai University Affiliated Hospital, China. The values of LSM, aspartate transaminase-to-platelet ratio index (APRI), gamma-glutamyl transpeptidase-to-platelet ratio (GPR), and fibrosis-4 (FIB-4) were evaluated in all admitted patients. The diagnostic value of APRI, GPR, FIB-4, and LSM was assessed using the receiver operating characteristic (ROC) curve. FIB-4 score (AUC=0.842; specificity=77.8%; sensitivity=80.7%; cut-off=2.824) was the best substitute for LSM from the three serum scoring models. The Cox regression model indicated that a FIB-4 score ≥2.824 was an independent predictor of prognosis for compensated hepatitis B-related LC (HR=1.15, 95%CI: 1.07-1.23, p<0.001). This study's findings suggested that FIB-4 could be the best substitute for LSM and may help to assess LC prognosis. Key Words: APRI, GPR, FIB-4, LSM, Diagnosis, Liver cirrhosis.

All-optical flip-flop based on hybrid square-rectangular bistable lasers.

A compact, simple, and bistable hybrid square-rectangular laser is experimentally demonstrated as an all-optical flip-flop memory. Controllable bistability is induced by two-mode competition, together with the saturable absorption at the square microcavity section. The all-optical set and reset operations are realized by injecting signal pulses at two-mode wavelengths, with the response times of 165 and 60 ps at the triggering pulse width of 100 ps and switching energies of 2.7 and 14.2 fJ, respectively. The robust hybrid-cavity design has an active area of 660 µm2 and permits efficient unidirectional single-mode lasing, low-power flip-flop operation, and superior fabrication tolerance for monolithic photonic integration.

Single-mode unidirectional-emission circular-side hexagonal resonator microlasers.

Circular-side hexagonal resonator (CSHR) microlasers connecting an output waveguide are proposed and demonstrated for enhancing the mode Q factor and realizing single-mode operation. Three-dimensional simulation results indicate that the CSHRs with an optimized deformation can greatly enhance mode Q factors. The CSHR microlasers with output waveguides are fabricated using a planar technology process. For a CSHR microlaser with a side length of 7.5 µm and an output waveguide width of 2 µm, single-mode operation is realized with a side-mode suppression ratio of 43 dB and a threshold current of 2.5 mA. Furthermore, flat small-signal modulation responses are obtained with a 3 dB bandwidth of 13 GHz.

Multicoherence wavelength generation based on integrated twin-microdisk lasers.

An effective method for multicoherence wavelength generation is experimentally demonstrated using an integrated twin-microdisk laser as a seeding source. Dual-wavelength lasing with variable wavelength spacing is achieved by adjusting injection currents independently. Using the integrated laser as a pump seed, we obtain multicoherence wavelength in a nonlinear optical fiber, which has a tunable frequency interval from 50 to 300 GHz. Ten waves with optical signal to noise ratio from 28 to 10 dB are produced at the frequency interval of 200 GHz and a pulse width of 1.2 ps. The high extinction ratio of the pulse trace indicates the high coherence in the mode-locked multiwavelength light source.

Trypsin pre-treatment corrects SRID over-estimation of immunologically active, pre-fusion HA caused by mixed immunoprecipitin rings.

Influenza vaccines are the primary intervention to prevent the substantial health burden of seasonal and pandemic influenza. Subunit and split influenza vaccines are formulated, released for clinical use, and tested for stability based on their content of immunologically active (capable of eliciting functional antibodies) hemagglutinin (HA). Single-radial immunodiffusion (SRID), the standard in vitro potency assay in the field, is believed to specifically detect immunologically active HA. We confirmed that, with conformationally homogeneous HA preparations, SRID specifically detected native, pre-fusion HA, which elicited influenza neutralizing and hemagglutination inhibiting (HI) antibodies in mice, and it did not detect low-pH stressed, post-fusion HA, which was selectively removed from the SRID gel during a blotting step and was significantly less immunologically active. This selective detection was due to the SRID format, not a conformational specificity of the sheep antiserum used in the SRID, as the same antiserum detected non-stressed and low-pH stressed HA similarly when used in an ELISA format. However, when low-pH stressed HA was mixed with non-stressed HA, SRID detected both forms in mixed immunoprecipitin rings, leading to over-quantification of pre-fusion HA. We previously reported that trypsin digestion of antigen samples selectively degrade stressed HA, so that an otherwise conformationally insensitive biophysical quantification technique, reversed-phase high pressure liquid chromatography (RP-HPLC), can specifically quantify trypsin-resistant, immunologically active, pre-fusion HA. Here, we report that trypsin digestion can also improve the specificity of SRID so that it can quantify immunologically active, pre-fusion HA when it is mixed with less immunologically active, post-fusion HA.

Narrow-linewidth microwave generation using AlGaInAs/InP microdisk lasers subject to optical injection and optoelectronic feedback.

Narrow-linewidth and low phase noise photonic microwave generation under sideband-injection locking are demonstrated using an 8-µm-radius AlGaInAs/InP microdisk laser subject to optical injection and optoelectronic feedback. Microdisk laser subject to external optical injection at the period-one state provides the microwave subcarrier seed signal, and the optoelectronic feedback serves as direct current modulation to stabilize and lock the generated microwave signal without using the electrical filter. High-quality photonic microwave signals are realized with the 3-dB linewidth of less than 1 kHz and the frequency tunable range from 8.8 to 17 GHz. Single sideband phase noise of -101 dBc/Hz is obtained at a frequency offset of 10 kHz for the generated 14.7 GHz signal. Furthermore, the dependences of photonic microwave signal on the optical injection and optoelectronic feedback parameters are investigated.

Dual-transverse-mode microsquare lasers with tunable wavelength interval.

A dual-transverse-mode microsquare laser with a tunable wavelength interval is designed and realized by using a square-ring-patterned contact window. For a 30-µm-side-length microsquare laser with the square-ring width of 4 µm, the wavelength interval varies from 0.25 to 0.37 nm with the intensity ratio less than 2.5 dB as the injection current increases from 89 to 108 mA. Based on the dual-transverse-mode microsquare laser, the microwave signals with the frequencies of 30.56, 32.70, 35.12, and 39.51 GHz and the 3-dB bandwidths of 47, 53, 54, and 47 MHz are obtained at the injection currents of 90, 95, 100, and 105 mA, respectively.

Thermal and high speed modulation characteristics for AlGaInAs/InP microdisk lasers.

Thermal and high speed modulation characteristics are investigated for a unidirectional-emission microdisk laser with a radius of 7 µm surrounded by BCB-cladding layer, with a threshold current of 1.5 mA at the temperature of 287 K. The lasing spectra under different widths of pulsed current are measured to characterize the temperature rise during the pulse period, and the thermal distribution in the microdisk laser is simulated by the finite-element modeling technique. A temperature rise of 25 K is estimated for the microdisk laser biased at 20 mA. Furthermore, small signal modulation response with 3dB bandwidth up to 20 GHz is obtained for the microdisk laser at the biasing current of 18 mA, and eye-diagrams at the modulation bit rates of 20, 25, and 30 GHz are also measured at the temperature of 287 K.

Profiles of B and T cell immune responses elicited by different forms of the hepatitis B virus surface antigen.

Gene-based hepatitis B virus (HBV) vaccines have been proposed as a novel approach to improve the immunogenicity toward non-responders and to allow for protection against potential viral escape mutants. Furthermore, there is significant interest in using DNA or viral vector vaccines to serve as therapeutic agents to treat chronic HBV infections that are resistant to existing drug therapies. However, the key protective antigen of HBV, the surface protein (HBsAg), can be expressed in three different sizes due to its multiple translational initiation sites: small, middle, and large forms of HBsAg. It is not clear whether the immunogenicity of these HBsAg is same, especially their ability to elicit HBsAg-specific B cell and T cell immune responses in addition to the traditional serum HBsAg-specific antibody responses. In the current study, the immunogenicity of three forms of HBsAg DNA vaccines was analyzed individually in a mouse model. Our results indicated that different forms of the HBsAg have unique immunogenicity profiles and this information is useful for the selection of optimal gene-based HBV vaccines for further improved prophylactic and therapeutic applications.

The mechanism of inhibition of HIV-1 env-mediated cell-cell fusion by recombinant cores of gp41 ectodomain.

N36(L6)C34 is a recombinant protein that forms a six-helix bundle with high thermal stability. It consists of the N-terminal heptad-repeat region (N36 peptide) and the C-terminal heptad-repeat region (C34) of HIV-1 gp41, connected by six polar amino acids. The protein inhibits HIV-1 envelope-induced membrane fusion. Whether inhibition occurs while N36(L6)C34 is in its six-helix bundle configuration was investigated. Mutating a critical residue within the N36 region to promote dissociation of C34 from the grooves of the N36 coiled coil reduced bundle stability and increased the inhibition of fusion. In contrast, mutating a key residue within the C34 region to reduce bundle stability decreased inhibitory potency. The data provide strong evidence that the proteins inhibit fusion while they expose their C34 segments, rather than as six-helix bundles. Thus, despite high thermal stability of the bundle, the recombinants' less folded structures are present in sufficient concentration to inhibit fusion at physiological temperatures.