The total IgM, IgA and IgG antibody responses to pneumococcal polysaccharide vaccination (Pneumovax®23) in a healthy adult population and patients diagnosed with primary immunodeficiencies

Humoral Immunity and Antibody Responses against Diphtheria, Tetanus, and Pneumococcus after Immune Effector Cell Therapies: A Prospective Study

Patients undergoing immune effector cell therapy (IECT) are at high risk for infections. We assessed seropositivity against pneumococcus, tetanus, and diphtheria in patients before and after IECT and the patients' response to vaccination. We enrolled patients who underwent IECT from January 2020 to March 2022. Antibody levels for diphtheria, tetanus, and pneumococcus were measured before IECT, at 1 month, and 3-6 months after. Eligible patients were vaccinated after IECT. In non-seroprotected patients, we discontinued testing. Before IECT, most patients had seroprotective antibody levels against tetanus (68/69, 99%) and diphtheria (65/69, 94%), but fewer did against pneumococcus (24/67, 36%). After IECT, all patients had seroprotective antibody levels for tetanus at 1 month (68/68) and 3-6 months (56/56). For diphtheria, 65/65 patients (100%) had seroprotective antibody levels at 1 month, and 48/53 (91%) did at 3-6 months. For pneumococcus, seroprotective antibody levels were identified in 91% (21/23) of patients at 1 month and 79% (15/19) at 3-6 months following IECT. Fifteen patients received a pneumococcal vaccine after IECT, but none achieved seroprotective response. One patient received the tetanus-diphtheria vaccine and had a seroprotective antibody response. Because some patients experience loss of immunity after IECT, studies evaluating vaccination strategies post-IECT are needed.

Comparative Transcriptome Profiling of mRNA and lncRNA of Mouse Spleens Inoculated with the Group ACYW135 Meningococcal Polysaccharide Vaccine

The Group ACYW135 meningococcal polysaccharide vaccine (MPV-ACYW135) is a classical common vaccine used to prevent Neisseria meningitidis serogroups A, C, Y, and W135, but studies on the vaccine at the transcriptional level are still limited. In the present study, mRNAs and lncRNAs related to immunity were screened from the spleens of mice inoculated with MPV-ACYW135 and compared with the control group to identify differentially expressed mRNAs and lncRNAs in the immune response. The result revealed 34375 lncRNAs and 41321 mRNAs, including 405 differentially expressed (DE) lncRNAs and 52 DE mRNAs between the MPV group and the control group. Results of GO and KEGG enrichment analysis turned out that the main pathways related to the immunity of target genes of those DE mRNAs and DE lncRNAs were largely associated with positive regulation of T cell activation, CD8-positive immunoglobulin production in mucosal tissue, alpha-beta T cell proliferation, negative regulation of CD4-positive, and negative regulation of interleukin-17 production, suggesting that the antigens of MPV-ACYW135 capsular polysaccharide might activate T cell related immune reaction in the vaccine inoculation. In addition, it was noted that Bach2 (BTB and CNC homolog 2), the target gene of lncRNA MSTRG.17645, was involved in the regulation of immune response in MPV-ACYW135 vaccination. This study provided a preliminary catalog of both mRNAs and lncRNAs associated with the proliferation and differentiation of body immune cells, which was worthy of further research to enhance the understanding of the biological immune process regulated by MPV-ACYW135.

Single-cell profiling of the antigen-specific response to BNT162b2 SARS-CoV-2 RNA vaccine

RNA-based vaccines against SARS-CoV-2 have proven critical to limiting COVID-19 disease severity and spread. Cellular mechanisms driving antigen-specific responses to these vaccines, however, remain uncertain. Here we identify and characterize antigen-specific cells and antibody responses to the RNA vaccine BNT162b2 using multiple single-cell technologies for in depth analysis of longitudinal samples from a cohort of healthy participants. Mass cytometry and unbiased machine learning pinpoint an expanding, population of antigen-specific memory CD4+ and CD8+ T cells with characteristics of follicular or peripheral helper cells. B cell receptor sequencing suggest progression from IgM, with apparent cross-reactivity to endemic coronaviruses, to SARS-CoV-2-specific IgA and IgG memory B cells and plasmablasts. Responding lymphocyte populations correlate with eventual SARS-CoV-2 IgG, and a participant lacking these cell populations failed to sustain SARS-CoV-2-specific antibodies and experienced breakthrough infection. These integrated proteomic and genomic platforms identify an antigen-specific cellular basis of RNA vaccine-based immunity.

Generation of cardio-protective antibodies after pneumococcal polysaccharide vaccine: Early results from a randomised controlled trial

BACKGROUND AND AIMS

Observational studies have demonstrated that the pneumococcal polysaccharide vaccine (PPV) is associated with reduced risk of cardiovascular events. This may be mediated through IgM antibodies to OxLDL, which have previously been associated with cardioprotective effects. The Australian Study for the Prevention through Immunisation of Cardiovascular Events (AUSPICE) is a double-blind, randomised controlled trial (RCT) of PPV in preventing ischaemic events. Participants received PPV or placebo once at baseline and are being followed-up for incident fatal and non-fatal myocardial infarction or stroke over 6 years.

METHODS

A subgroup of participants at one centre (Canberra; n = 1,001) were evaluated at 1 month and 2 years post immunisation for changes in surrogate markers of atherosclerosis, as pre-specified secondary outcomes: high-sensitive C-reactive protein (CRP), pulse wave velocity (PWV), and carotid intima-media thickness (CIMT). In addition, 100 participants were randomly selected in each of the intervention and control groups for measurement of anti-pneumococcal antibodies (IgG, IgG2, IgM) as well as anti-OxLDL antibodies (IgG and IgM to CuOxLDL, MDA-LDL, and PC-KLH).

RESULTS

Concentrations of anti-pneumococcal IgG and IgG2 increased and remained high at 2 years in the PPV group compared to the placebo group, while IgM increased and then declined, but remained detectable, at 2 years. There were statistically significant increases in all anti-OxLDL IgM antibodies at 1 month, which were no longer detectable at 2 years; there was no increase in anti-OxLDL IgG antibodies. There were no significant changes in CRP, PWV or CIMT between the treatment groups at the 2-year follow-up.

CONCLUSIONS

PPV engenders a long-lasting increase in anti-pneumococcal IgG, and to a lesser extent, IgM titres, as well as a transient increase in anti-OxLDL IgM antibodies. However, there were no detectable changes in surrogate markers of atherosclerosis at the 2-year follow-up. Long-term, prospective follow-up of clinical outcomes is continuing to assess if PPV reduces CVD events.

Yields and Immunomodulatory Effects of Pneumococcal Membrane Vesicles Differ with the Bacterial Growth Phase

Streptococcus pneumoniae infections are a leading cause of death worldwide. Bacterial membrane vesicles (MVs) are promising vaccine candidates because of the antigenic components of their parent microorganisms. Pneumococcal MVs exhibit low toxicity towards several cell lines, but their clinical translation requires a high yield and strong immunogenic effects without compromising immune cell viability. MVs are isolated during either the stationary phase (24 h) or death phase (48 h), and their yields, immunogenicity and cytotoxicity in human primary macrophages and dendritic cells have been investigated. Death-phase vesicles showed higher yields than stationary-phase vesicles. Both vesicle types displayed acceptable compatibility with primary immune cells and several cell lines. Both vesicle types showed comparable uptake and enhanced release of the inflammatory cytokines, tumor necrosis factor and interleukin-6, from human primary immune cells. Proteomic analysis revealed similarities in vesicular immunogenic proteins such as pneumolysin, pneumococcal surface protein A, and IgA1 protease in both vesicle types, but stationary-phase MVs showed significantly lower autolysin levels than death-phase MVs. Although death-phase vesicles produced higher yields, they lacked superiority to stationary-phase vesicles as vaccine candidates owing to their similar antigenic protein cargo and comparable uptake into primary human immune cells.

Single-Cell Profiling of the Antigen-Specific Response to BNT162b2 SARS-CoV-2 RNA Vaccine

RNA-based vaccines against SARS-CoV-2 are critical to limiting COVID-19 severity and spread. Cellular mechanisms driving antigen-specific responses to these vaccines, however, remain uncertain. We used single-cell technologies to identify and characterized antigen-specific cells and antibody responses to the RNA vaccine BNT162b2 in longitudinal samples from a cohort of healthy donors. Mass cytometry and machine learning pinpointed a novel expanding, population of antigen-specific non-canonical memory CD4 ⁺ and CD8 ⁺ T cells. B cell sequencing suggested progression from IgM, with apparent cross-reactivity to endemic coronaviruses, to SARS-CoV-2-specific IgA and IgG memory B cells and plasmablasts. Responding lymphocyte populations correlated with eventual SARS-CoV-2 IgG and a donor lacking these cell populations failed to sustain SARS-CoV-2-specific antibodies and experienced breakthrough infection. These integrated proteomic and genomic platforms reveal an antigen-specific cellular basis of RNA vaccine-based immunity.

ONE SENTENCE SUMMARY

Single-cell profiling reveals the cellular basis of the antigen-specific response to the BNT162b2 SARS-CoV-2 RNA vaccine.

The clinical relevance of IgM and IgA anti-pneumococcal polysaccharide ELISA assays in patients with suspected antibody deficiency

Unlike immunoglobulin (Ig)G pneumococcal polysaccharide (PnPS)‐antibodies, PnPS IgA and IgM‐antibodies are not routinely determined for the assessment of immunocompetence. It is not yet known whether an isolated inability to mount a normal IgM or IgA‐PnPS response should be considered a relevant primary antibody deficiency (PAD). We studied the clinical relevance of anti‐PnPS IgM and IgA‐assays in patients with suspected primary immunodeficiency in a large teaching hospital in ’s‐Hertogenbosch, the Netherlands. Serotype‐specific‐PnPS IgG assays were performed; subsequently, 23‐valent‐PnPS IgG assays (anti‐PnPS IgG assays), and later anti‐PnPS IgA and IgM assays, were performed in archived material (240 patients; 304 samples). Eleven of 65 pre‐ and six of 10 post‐immunization samples from good responders to PnPS serotype‐specific IgG testing had decreased anti‐PnPS IgA and/or IgM titres. Of these, three pre‐ and no post‐immunization samples were from patients previously classified as ‘no PAD’. Determination of anti‐PnPS IgA and IgM in addition to anti‐PnPS IgG did not reduce the need for serotype‐specific PnPS IgG testing to assess immunocompetence [receiver operating characteristic (ROC) analysis of post‐immunization samples: anti‐PnPS IgA + IgG area under the curve (AUC) = 0.80, 95% confidence interval (CI) = 0.63–0.97; anti‐PnPS IgM + IgG AUC 0.80, 95% CI = 0.62–0.98; anti‐PnPS IgA + IgG + IgM AUC = 0.71, 95% CI = 0.51–0.91; anti‐PnPS IgG AUC = 0.93, 95% CI = 0.85–1.00]. Our data show that patients classified as having an intact antibody response based on measurement of serotype‐specific PnPS IgG can still display impaired anti‐PnPS IgM and IgA responses, and that the additional measurement of anti‐PnPS IgA and IgM could not reduce the need for serotype‐specific IgG testing. Future studies are needed to investigate the clinical relevance of potential ‘specific IgA or IgM antibody deficiency’ in patients with recurrent airway infections in whom no PAD could be diagnosed according to the current definitions.

Inferior outcomes in lung transplant recipients with serum Pseudomonas aeruginosa specific cloaking antibodies

BACKGROUND

Chronic Lung Allograft Dysfunction (CLAD) limits long-term survival following lung transplantation. Colonization of the allograft by Pseudomonas aeruginosa is associated with an increased risk of CLAD and inferior overall survival. Recent experimental data suggests that 'cloaking' antibodies targeting the O-antigen of the P. aeruginosa lipopolysaccharide cell wall (cAbs) attenuate complement-mediated bacteriolysis in suppurative lung disease.

METHODS

In this retrospective cohort analysis of 123 lung transplant recipients, we evaluated the prevalence, risk factors and clinical impact of serum cAbs following transplantation.

RESULTS

cAbs were detected in the sera of 40.7% of lung transplant recipients. Cystic fibrosis and younger age were associated with increased risk of serum cAbs (CF diagnosis, OR 6.62, 95% CI 2.83-15.46, p < .001; age at transplant, OR 0.69, 95% CI 0.59-0.81, p < .001). Serum cAbs and CMV mismatch were both independently associated with increased risk of CLAD (cAb, HR 4.34, 95% CI 1.91-9.83, p < .001; CMV mismatch (D+/R-), HR 5.40, 95% CI 2.36-12.32, p < .001) and all-cause mortality (cAb, HR 2.75, 95% CI 1.27-5.95, p = .010, CMV mismatch, HR 3.53, 95% CI 1.62-7.70, p = .002) in multivariable regression analyses.

CONCLUSIONS

Taken together, these findings suggest a potential role for 'cloaking' antibodies targeting P. aeruginosa LPS O-antigen in the immunopathogenesis of CLAD.

Development of anti-human IgM nanobodies as universal reagents for general immunodiagnostics

Nanobodies are the smallest antibody fragments which bind to antigens with high affinity and specificity. Due to their outstanding physicochemical stability, simplicity and cost-effective production, nanobodies have become powerful agents in therapeutic and diagnostic applications. In this work, the advantages of nanobodies were exploited to develop generic and standardized anti-human IgM reagents for serology and IgM⁺ B-cell analysis. Selection of anti-IgM nanobodies was carried out by evaluating their yields, stability, binding kinetics and cross-reactivity with other Ig isotypes. High affinity nanobodies were selected with dissociation constants (KDs) in the nM range and high sensitivities for detection of total IgM by ELISA. The nanobodies also proved to be useful for capturing IgM in the serodiagnosis of an acute infection as demonstrated by detection of specific IgM in sera of dengue virus patients. Finally, due to the lack of an Fc region, the selected nanobodies do not require Fc receptor blocking steps, facilitating the immunophenotyping of IgM⁺ cells by flow cytometry, an important means of diagnosis of immunodeficiencies and B-cell lymphoproliferative disorders. This work describes versatile anti-IgM nanobodies that, due to their recombinant nature and ease of reproduction at low cost, may represent an advantageous alternative to conventional anti-IgM antibodies in research and diagnosis.

Phenotypic analysis of T follicular helper and T follicular regulatory cells in primary selective IgM deficiency

Selective IgM deficiency (SIgMD) is a rare immunodeficiency characterized by serum IgM below two standard of mean, and normal IgG and IgA levels. Both in human and mice with selective IgM deficiency, germinal centers cells are decreased. The development of germinal center and humoral immunity are regulated in part by follicular helper T (T_FH) and follicular regulatory T (T_FR) cells. However, the analysis of circulating T_FH (cT_FH) and T_FR (cT_FR) cells in the pathogenesis of SIgMD has not been explored. We observed lower percentage of cT_FR cells in SIgMD patients than in control group. However, we did not observe any significant difference in the percentage of cT_FH cells and their subsets between both experimental groups. When data were analyzed according to specific antibody response to pneumococcal polysaccharide, we observed a higher percentage of cT_FH cells in SIgMD patients with specific antibody deficiency than in SIgMD patients with normal specific antibody response. Our results suggest that cT_FH cells and their subsets are preserved in SIgMD patients. However, the role of lower percentage of cT_FR cells in the pathogenesis of this immunodeficiency is not clear.

Response to the conjugate pneumococcal vaccine (PCV13) in patients with chronic lymphocytic leukemia (CLL)

Pneumococcal (PC) vaccination is recommended for patients with chronic lymphocytic leukemia (CLL). However, response to vaccines has been investigated in a small series of CLL patients. We analyzed the antibody response and outcomes of 112 CLL patients who received the 13-valent pneumococcal conjugate vaccine (PCV13). An immune response was defined by a twofold increase in the PC-IgG levels assessed by ELISA. The median age of patients was 68 years, 23.2% showed IgG levels ≤ 400 mg/L, 6.3% progressive disease, 52% unmutated IGHV. Twenty-two (19.6%) patients were treatment-naïve and 90 (80.4%) previously treated (40.2% front-line chemoimmunotherapy; ibrutinib first/advanced-line, 9.8%/21.4%; idelalisib advanced-line, 8.9%). Nine (8%) patients developed an immune response, eight treatment-naive, and one on front-line ibrutinib. No responses were observed in patients previously treated with chemoimmunotherapy. Age ≥ 60 years (p = 0.007), IgG levels < 400 mg/L (p < 0.0001), prior treatment (p < 0.0001), and signs of disease progression (p = 0.04) were associated with a lower response rate. Pneumonia-free survival was significantly shorter in patients with clinical signs of progressive disease (HR, 8.39), prior pneumonia (HR, 7.03), and TP53 disruption (HR, 2.91). In conclusion, our results suggest that vaccination should be offered at diagnosis to CLL patients with early stage and stable disease who have better resources for an effective immune response.

Influence of immune aging on vaccine responses

Impaired vaccine responses in older individuals are associated with alterations in both the quantity and quality of the T-cell compartment with age. As reviewed herein, the T-cell response to vaccination requires a fine balance between the generation of inflammatory effector T cells versus follicular helper T (TFH) cells that mediate high-affinity antibody production in tandem with the induction of long-lived memory cells for effective recall immunity. During aging, we find that this balance is tipped where T cells favor short-lived effector but not memory or TFH responses. Consistently, vaccine-induced antibodies commonly display a lower protective capacity. Mechanistically, multiple, potentially targetable, changes in T cells have been identified that contribute to these age-related defects, including posttranscription regulation, T-cell receptor signaling, and metabolic function. Although research into the induction of tissue-specific immunity by vaccines and with age is still limited, current mechanistic insights provide a framework for improved design of age-specific vaccination strategies that require further evaluation in a clinical setting.

Focusing on Good Responders to Pneumococcal Polysaccharide Vaccination in General Hospital Patients Suspected for Immunodeficiency. A Decision Tree Based on the 23-Valent Pneumococcal IgG Assay

Background and Aim: Recently, the 23-valent IgG-assay was suggested as screening assay to identify poor responders to pneumococcal polysaccharide (PnPS)-vaccination with the serotype-specific assay as a second-line test. However, in a low pre-test probability general hospital setting predicting good responders could be more valuable to reduce the number of samples needing serotyping. Methods: Serotype-specific PnPS antibody-assays were performed for suspected immunodeficiency in two Dutch general hospitals (Jeroen Bosch Hospital, 's-Hertogenbosch; Elisabeth Tweesteden Hospital, Tilburg). 23-Valent PnPS antibody-assays were subsequently performed in archived material. Data were analyzed using receiver operating characteristic curves (AUC) and agreement indices (ICC). Results: Sera of 284 patients (348 samples) were included; 23-valent IgG-titres and the corresponding sum of PnPS-serotype specific antibodies showed moderate correlation (ICC = 0.63). In 232 conjugated-pneumococcal-vaccine-naïve patients (270 samples), a random 23-valent IgG-titer could discriminate between samples with and without ≥7/11, ≥7/13, or ≥6/9 pneumococcal serotypes when both cut-off values 0.35 and 1.0 μg/ml were used (AUC 0.86 and 0.92, respectively). All patients with a pre-immunization-titer ≥38.2 μg/ml and/or post-immunization-titer ≥96.1 μg/ml and none with a post-immunization-titer ≤38.5 μg/ml exhibited a good response to PnPS vaccination. Using these breakpoints as screening test to predict good responders, only 24% of patients would require further serotyping, as opposed to 68% if breakpoints to predict poor responders would have been used. Conclusion: In a low pre-test probability setting, the 23-valent IgG-assay proved to be a reliable screening test for good responders in conjugated-pneumococcal-vaccine-naïve patients, reducing the overall number of patient samples needing further serotyping, thus reducing overall costs of pneumococcal vaccination response assessment.

Pneumococcal vaccination responses in adults with subnormal IgG subclass concentrations

BACKGROUND

We sought to compare Pneumovax®23 responses in adults with subnormal IgG subclass concentrations. We studied adults with normal total IgG, frequent/severe respiratory infection, and subnormal IgG1, IgG3, or IgG1 + IgG3 before and after Pneumovax®23. We defined response as serotype-specific IgG > 1.3 μg/mL and aggregate response as IgG > 1.3 μg/mL for ≥70% of all serotypes tested. We compared patients with and without serotype-specific responses and performed logistic regression on aggregate responses using: age; male sex; body mass index; autoimmune condition(s); atopy; other allergies; subnormal IgGSc immunophenotypes; IgA; and IgM.

RESULTS

There were 59 patients (mean age 44 ± 13 (SD) years; 83.1% women). Median days between pre- and post-Pneumovax®23 testing was 33 (range 19-158). The median post-vaccination summated concentration of serotype-specific IgG was higher in patients with subnormal IgG1 than subnormal IgG3 (responders and non-responders). All subnormal IgG1 + IgG3 non-responders responded to serotypes 8, 9 and 26, unlike other non-responders. Subnormal IgG3 responders had lower responses to serotypes 1, 4, 12, 23, 26, and 51. Subnormal IgG3 non-responders had higher responses to serotypes 1, 3, 8, 9, 12, 14, 19, 51, and 56. Response rates decreased with increasing age. Aggregate responders were: subnormal IgG1, 54%; IgG3, 46%; and IgG1 + IgG3, 46%. Regression on aggregate response revealed lower response with male sex (odds ratio 0.09 [95% CI 0.01, 0.77]) and atopy (0.17 [0.03, 0.83]).

CONCLUSIONS

Serotype-specific IgG responses to Pneumovax®23 were greater in patients with subnormal IgG1 than subnormal IgG3. Male sex and atopy were associated with lower aggregate responses.