Loss of anti-spike antibodies following mRNA vaccination for COVID-19 among patients with multiple myeloma.

BACKGROUND: Multiple myeloma (MM) patients have variable responses to mRNA vaccination to COVID-19. Little is known regarding their vaccine-induced antibody levels over time. METHODS: We monitored spike IgG antibody levels over 24 weeks among a subset of 18 MM patients who showed a full response after two mRNA vaccinations. RESULTS: MM patients had a more rapid decline in antibody levels as compared to eight healthy controls, with power law half-lives of 72 days (vs. 107 days) and exponential half-lives of 37 days (vs. 51 days). The patients with longer SARS-CoV-2 antibody half-lives were more likely to have undetectable monoclonal protein than those with shorter half-lives, suggesting better disease control may correlate with longer duration of vaccine-induced antibodies. Regardless, by 16 weeks post-second dose of mRNA vaccination, the majority of patients had antibody levels below 250 binding arbitrary units per milliliter, which would be unlikely to contribute to preventing COVID-19. CONCLUSIONS: Thus, even MM patients who respond adequately to vaccination are likely to require more frequent booster doses than the general population.

Cladophialophora bantiana orbital cellulitis after penetrating injury.

A 75-year-old immunocompetent male presented with a right orbital cellulitis after a foreign body penetrating injury. He was taken for orbitotomy with foreign body removal and started on broad-spectrum antibiotics. Intra-operative cultures were positive for Cladophialophora bantiana, a mold known for causing brain abscesses with no prior reports of orbital invasion in the literature. Following culture results, the patient was managed with voriconazole and required multiple orbitotomies and washouts for infection control.

Third dose of an mRNA COVID-19 vaccine for patients with multiple myeloma.

We have reported that IgG antibody responses following two mRNA COVID-19 vaccinations are impaired among patients with multiple myeloma (MM). In the current study, sixty-seven patients with MM were tested for anti-spike IgG antibodies 0-60 days prior to their first vaccination, 14-28 days following the second dose, and both before and 14-28 days after their third dose of the mRNA-1273 or BNT162b2 vaccines. After the first two doses, most patients' (93 %) antibody levels declined to ineffective levels (<250 BAU/mL) prior to their third dose (D3). D3 elicited responses in 84 % of patients (61 % full response and 22 % partial response). The third vaccination increased antibody levels (average = 370.4 BAU/mL; range, 1.0-8977.3 BAU/mL) relative to just prior to D3 (average = 25.0 BAU/mL; range, 1.0-683.8 BAU/mL) and achieved higher levels than peak levels after the first two doses (average = 144.8 BAU/mL; range, 1.0-4,284.1 BAU/mL). D3 response positively correlated with mRNA-1273, a > 10-fold change from baseline for the two-dose series, switching from BNT162b2 to mRNA-1273 for D3, and treatment with elotuzumab and an immunomodulatory agent. Lower antibody levels prior to D3, poorer overall response to first two doses, and ruxolitinib or anti-CD38 monoclonal antibody treatment negatively correlated with D3 response. Our results show encouraging activity of the third vaccine, even among patients who failed to respond to the first two vaccinations. The finding of specific factors that predict COVID-19 antibody levels will help advise patients and healthcare professionals on the likelihood of responses to further vaccinations.

Severe breakthrough COVID-19 with a heavily mutated variant in a multiple myeloma patient 10 weeks after vaccination.

BACKGROUND: Patients with multiple myeloma have unpredictable responses to vaccination for COVID-19. Anti-spike antibody levels can determine which patients develop antibodies at levels similar to healthy controls, and are a known correlate of protection. CASE REPORT: A multiple myeloma patient developed protective anti-spike antibodies after vaccination (608 IU/mL), but nonetheless developed severe breakthrough COVID-19 just 10 weeks following his second vaccination with mRNA-1273. RESULTS: Sequencing of the viral isolate revealed an extensively mutated variant with 10 spike protein mutations, including E484Q and N440K. Serology testing showed a dramatic decline in anti-spike antibodies immediately prior to virus exposure. CONCLUSIONS: Multiple myeloma patients who do develop detectable antibody responses to vaccination may be at increased risk for breakthrough infections due to rapid decline in antibody levels. Viral variants with immune escape mutations such as N440K, also seen independently in the SARS-CoV-2 Omicron variant (B.1.1.529) and in viral passaging experiments, likely require a higher level of anti-spike antibodies to prevent severe COVID-19.

Single-Amplicon Multiplex Real-Time Reverse Transcription-PCR with Tiled Probes To Detect SARS-CoV-2 spike Mutations Associated with Variants of Concern.

To provide an accessible and inexpensive method to surveil for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutations, we developed a multiplex real-time reverse transcription-PCR (rRT-PCR) assay, the Spike single-nucleotide polymorphism (SNP) assay, to detect specific mutations in the spike receptor binding domain. A single primer pair was designed to amplify a 348-bp region of spike, and probes were initially designed to detect K417, E484K, and N501Y. The assay was evaluated using characterized variant sample pools and residual nasopharyngeal samples. Variant calls were confirmed by SARS-CoV-2 genome sequencing in a subset of samples. Subsequently, a fourth probe was designed to detect L452R. The lower limit of 95% detection was 2.46 to 2.48 log10 genome equivalents (GE)/ml for the three initial targets (∼1 to 2 GE/reaction). Among 253 residual nasopharyngeal swabs with detectable SARS-CoV-2 RNA, the Spike SNP assay was positive in 238 (94.1%) samples. All 220 samples with threshold cycle (CT) values of <30 for the SARS-CoV-2 N2 target were detected, whereas 18/33 samples with N2 CT values of ≥30 were detected. Spike SNP results were confirmed by sequencing in 50/50 samples (100%). Addition of the 452R probe did not affect performance for the original targets. The Spike SNP assay accurately identifies SARS-CoV-2 mutations in the receptor binding domain, and it can be quickly modified to detect new mutations that emerge.

Response to mRNA vaccination for COVID-19 among patients with multiple myeloma.

Multiple myeloma (MM) patients are at higher risk for severe COVID-19. Their mRNA vaccination response against SARS-CoV-2 is unknown. Thus, we analyzed responses to mRNA vaccination against COVID-19 among these patients. Using an ELISA-based assay that detects IgG antibodies to SARS-CoV-2 spike protein, we determined serum antibody levels prior to immunization and 12-21 and 14-21 days following the first and second vaccinations, respectively, with mRNA-1273 (Moderna) or BNT162b2 (Pfizer/BioNTech) among 103 MM patients (96 and 7 with active and smoldering disease, respectively). We stratified patients into clinically relevant responders (>250 IU/mL), partial responders (50-250 IU/mL, which was above pre-COVID-19 background), and nonresponders (<50 IU/mL). Smoldering MM patients responded better than those with active disease. Only 45% of active MM patients developed an adequate response, while 22% had a partial response. Lower spike antibody levels were associated with older age, impaired renal function, low lymphocyte counts, reduced uninvolved immunoglobulin levels, > second line of treatment, and among those not in complete remission. Patients who received mRNA-1273 vaccine had higher anti-spike antibody levels than those who were vaccinated with BNT162b2. Thus, most MM patients have impaired responses to mRNA vaccination against COVID-19, and specific clinical and myeloma-related characteristics predict vaccine responsiveness.

Expression, Purification, and Crystallization of HSV-1 Glycoproteins for Structure Determination.

Herpes simplex viruses utilize glycoproteins displayed on the viral envelope to perform a variety of functions in the viral infectious cycle. Structural and functional studies of these viral glycoproteins can benefit from biochemical, biophysical, and structural analysis of purified proteins. Here, we describe a general protocol for expression and purification of viral glycoproteins from insect cells based on those developed for the HSV-1 gB and HSV-2 gH/gL ectodomains as well as the protocol for crystallization of these glycoproteins. This protocol can be used for generating milligram amounts of wild-type (WT) or mutant gB and gH/gL ectodomains or can be adapted to produce purified ectodomains of glycoproteins from HSV or other herpesviruses for biochemical and structural studies.

Expression, purification, and crystallization of HSV-1 glycoproteins for structure determination.

HSV glycoproteins play important roles in the viral infectious cycle, particularly viral entry into the cell. Here we describe the protocol for expression, purification, and crystallization of viral glycoproteins based on those developed for the HSV-1 gB and HSV-2 gH/gL ectodomains. These protocols can be used for generating milligram amounts of wild-type (WT) or mutant gB and gH/gL ectodomains or can be adapted to produce purified ectodomains of other HSV glycoproteins for biochemical and structural studies.

Extensive mutagenesis of the HSV-1 gB ectodomain reveals remarkable stability of its postfusion form.

Viral fusogens mediate the merger of the viral envelope and cellular membrane during viral entry. These proteins share little sequence similarity but all are thought to act by refolding through a series of conformational intermediates from the metastable prefusion form to the stable postfusion form. Crystal structures of both prefusion and postfusion forms have illuminated the conformational pathways of several viral fusogens. By contrast, only the structure of the postfusion form is available for glycoprotein B (gB), the conserved fusogen of herpesviruses. To gain insight into the nature of the fusogenic conformational changes in gB, we used several approaches aimed at engineering the prefusion form of the herpes simplex virus type 1 gB ectodomain, including modifications intended to stabilize the prefusion form and novel mutations aimed at destabilizing the postfusion form. We found that the postfusion conformation of gB is remarkably stable and resistant to perturbations. Several mutations successfully destabilized the gB trimer, identifying regions that are critical for the stability of the postfusion form. Yet, none of the constructs adopted the prefusion conformation. We propose that the soluble ectodomain of gB folds into the postfusion form without first adopting the prefusion intermediate. These results suggest that other regions of gB, including the transmembrane region and the cytoplasmic domain, may be necessary to establish and maintain the metastable prefusion conformation.

Stuck in the middle: structural insights into the role of the gH/gL heterodimer in herpesvirus entry.

Enveloped viruses enter cells by fusing the viral and cellular membranes, and most use a single viral envelope protein that combines receptor-binding and fusogenic functions. In herpesviruses, these functions are distributed among multiple proteins: the conserved fusion protein gB, various non-conserved receptor-binding proteins, and the conserved gH/gL heterodimer that curiously lacks an apparent counterpart in other enveloped viruses. Recent structural studies of gH/gL from HSV-2 and EBV revealed a unique complex with no structural or functional similarity to other viral proteins. Here we analyzed gH/gL structures and highlighted important functional regions. We propose that gH/gL functions as an adaptor that transmits the triggering signals from various non-conserved inputs to the highly conserved fusion protein gB.

Structural basis of local, pH-dependent conformational changes in glycoprotein B from herpes simplex virus type 1.

Herpesviruses enter cells by membrane fusion either at the plasma membrane or in endosomes, depending on the cell type. Glycoprotein B (gB) is a conserved component of the multiprotein herpesvirus fusion machinery and functions as a fusion protein, with two internal fusion loops, FL1 and FL2. We determined the crystal structures of the ectodomains of two FL1 mutants of herpes simplex virus type 1 (HSV-1) gB to clarify whether their fusion-null phenotypes were due to global or local effects of the mutations on the structure of the gB ectodomain. Each mutant has a single point mutation of a hydrophobic residue in FL1 that eliminates the hydrophobic side chain. We found that neither mutation affected the conformation of FL1, although one mutation slightly altered the conformation of FL2, and we conclude that the fusion-null phenotype is due to the absence of a hydrophobic side chain at the mutated position. Because the ectodomains of the wild-type and the mutant forms of gB crystallized at both low and neutral pH, we were able to determine the effect of pH on gB conformation at the atomic level. For viruses that enter cells by endocytosis, the low pH of the endosome effects major conformational changes in their fusion proteins, thereby promoting fusion of the viral envelope with the endosomal membrane. We show here that upon exposure of gB to low pH, FL2 undergoes a major relocation, probably driven by protonation of a key histidine residue. Relocation of FL2, as well as additional small conformational changes in the gB ectodomain, helps explain previously noted changes in its antigenic and biochemical properties. However, no global pH-dependent changes in gB structure were detected in either the wild-type or the mutant forms of gB. Thus, low pH causes local conformational changes in gB that are very different from the large-scale fusogenic conformational changes in other viral fusion proteins. We propose that these conformational changes, albeit modest, play an important functional role during endocytic entry of HSV.