Influenza‐specific IgG1⁺ memory B‐cell numbers increase upon booster vaccination in healthy adults but not in patients with predominantly antibody deficiency

Abstract

Background. Annual influenza vaccination is recommended to all individuals over 6 months of age, including predominantly antibody deficiency (PAD) patients. Vaccination responses are typically evaluated by serology, and because PAD patients are by definition impaired in generating IgG and receive immunoglobulin replacement therapy (IgRT), it remains unclear whether they can mount an antigen-specific response. Objective. To quantify and characterise the antigen-specific memory B (Bmem) cell compartment in healthy controls and PAD patients following an influenza booster vaccination. Methods. Recombinant hemagglutinin (HA) from the A/Michigan/2015 H1N1 (AM15) strain with an AviTag was generated in a mammalian cell line, and following targeted biotinylation, was tetramerised with BUV395 or BUV737 streptavidin conjugates. Multicolour flow cytometry was applied on blood samples before and 28 days after booster influenza vaccination in 16 healthy controls and five PAD patients with circulating Bmem cells. Results. Recombinant HA tetramers were specifically recognised by 0.5-1% of B cells in previously vaccinated healthy adults. HA-specific Bmem cell numbers were significantly increased following booster vaccination and predominantly expressed IgG1. Similarly, PAD patients carried HAspecific Bmem cells, predominantly expressing IgG1. However, these numbers were lower than in controls and did not increase following booster vaccination. Conclusion. We have successfully identified AM15-specific Bmem cells in healthy controls and PAD patients. The presence of antigen-specific Bmem cells could offer

Pattern of circulating SARS‐CoV‐2‐specific antibody‐secreting and memory B‐cell generation in patients with acute COVID‐19

“…The proportion of RBD‐specific IgM or IgG Bmem cells in patients with COVID‐19 ranged from 4000 to 200 000 ASCs per 10 6 cells in the total B‐cell population. In other viral infections, comparable number of Bmem cells has been observed 35,41–43 …”

Rapid and lasting generation of B-cell memory to SARS-CoV-2 spike and nucleocapsid proteins in COVID-19 disease and convalescence

“…2 standard deviations (2SD) above the median of healthy controls ( Figure 2B and C ). All controls and patients had detectable levels of IgG to hemagglutinin (HA) of influenza H1N1 strain A/Michigan/45/2015 ( Figure 2D ) (Hartley et al, 2020), which was a recommended strain in the quadrivalent annual vaccine from 2017-2019 (Australian Immunisation Handbook, 2018). There was no significant difference in HA antibody levels between the patient and control groups.…”

“…phycoerythrin (PE) and allophycocyanin (APC)) (Brouwer et al, 2020; Juno et al, 2020; Kaneko et al, 2020; Liu et al, 2019; Rodda et al, 2020; Wheatley et al, 2016; Zhou et al, 2020). To further overcome this limitation, we used non-protein polymer fluorochromes, which exhibited minimal non-specific B-cell binding and increased the sensitivity of our assay (Hartley et al, 2020).…”

Flow Cytometry: From Experimental Design to Its Application in the Diagnosis and Monitoring of Respiratory Diseases

“…Table 1 shows a summary of the conventional diagnostic method to respiratory diseases, and it is contrasted with the alternatives that could be evaluated by FCM. [D] AILRT Influenza [E] RT-PCR Lung exploration Cell maps to identify variations of PBMC based on [F] t-SNE analysis [62,66] Microsphere-based antibody assay [63,64] Hemagglutinin-specific memory B cells [65] SARS-CoV-2 [G] NAAT [E] RT-PCR Serological testing…”

“…Under influenza context, it has been suggested that the use of microsphere-based flow cytometry immunoassay allows the functional characterization of influenza viruses, although mAb recognizes virus proteins and distinguishes between the inactivated virus and influenza virions; moreover, using this tool also allows the functional assessment of relative receptor affinity [ 63 , 64 ]. Recently, through FCM, hemagglutinin-specific memory B cells that express IgG1 were identified in previously vaccinated healthy adults; this result provides alternatives to evaluate the immune response as a response to booster vaccination or as a complementary test to diagnosis [ 65 ].…”