Class Switch Recombination Defects: impact on B cell maturation and antibody responses

Interaction of Bacteriophages with the Immune System: Induction of Bacteriophage-Specific Antibodies

In all cases when a bacteriophage makes a direct contact with a mammalian organism, it may challenge the mammalian immunological system. Its major consequence is the production of antibodies specific to the bacteriophage, particularly IgM, IgG, and IgA as the typical response. Here we present protocols applicable in studies of the ability of bacteriophage to induce specific antibodies; immunization to whole virions or to isolated phage proteins has been included. The protocols have been divided into three parts: purification, immunization, and detection (enzyme-linked immunosorbent assay, ELISA).

Clinical and Immunological Features, Genetic Variants, and Outcomes of Patients with CD40 Deficiency

PURPOSE

Inherited deficiencies of CD40 and CD40 ligand (CD40L) reflect the crucial immunological functions of CD40-CD40L interaction/signaling. Although numerous studies have provided a detailed description of CD40L deficiency, reports of CD40 deficiency are scarce. Herein, we describe the characteristics of all reported patients with CD40 deficiency.

METHODS

The PubMed, Embase and Web of Science databases were searched for relevant literature published till 7th August 2023. Study deduplication and identification of relevant reports was performed using the online PICO Portal. The data were extracted using a pre-designed data extraction form and the SPSS software was used for analysis.

RESULTS

Systematic literature review revealed 40 unique patients with CD40 deficiency. Respiratory tract and gastrointestinal infections were the predominant clinical manifestations (observed in 93% and 57% patients, respectively). Sclerosing cholangitis has been reported in nearly one-third of patients. Cryptosporidium sp. (29%) and Pneumocystis jirovecii (21%) were the most common microbes identified. Very low to undetectable IgG levels and severely reduced/absent switch memory B cells were observed in all patients tested/reported. Elevated IgM levels were observed in 69% patients. Overall, splice-site and missense variants were the most common (36% and 32%, respectively) molecular defects identified. All patients were managed with immunoglobulin replacement therapy and antimicrobial prophylaxis was utilized in a subset. Hematopoietic stem cell transplantation (HSCT) has been performed in 45% patients (curative outcome observed in 73% of these patients). Overall, a fatal outcome was reported in 21% patients.

CONCLUSIONS

We provide a comprehensive description of all important aspects of CD40 deficiency. HSCT is a promising curative treatment option for CD40 deficiency.

Biomarkers detected in cord blood predict vaccine responses in young infants

Introduction

Factors influencing vaccine immune priming in the first year of life involve both innate and adaptive immunity but there are gaps in understanding how these factors sustain vaccine antibody levels in healthy infants. The hypothesis was that bioprofiles associated with B cell survival best predict sustained vaccine IgG levels at one year.

Methods

Longitudinal study of plasma bioprofiles in 82 term, healthy infants, who received standard recommended immunizations in the United States, with changes in 15 plasma biomarker concentrations and B cell subsets associated with germinal center development monitored at birth, soon after completion of the initial vaccine series at 6 months, and prior to the 12-month vaccinations. Post vaccination antibody IgG levels to Bordetella pertussis, tetanus toxoid, and conjugated Haemophilus influenzae type B (HiB) were outcome measures.

Results

Using a least absolute shrinkage and selection operator (lasso) regression model, cord blood (CB) plasma IL-2, IL-17A, IL-31, and soluble CD14 (sCD14) were positively associated with pertussis IgG levels at 12 months, while CB plasma concentrations of APRIL and IL-33 were negatively associated. In contrast, CB concentrations of sCD14 and APRIL were positively associated with sustained tetanus IgG levels. A separate cross-sectional analysis of 18 mother/newborn pairs indicated that CB biomarkers were not due to transplacental transfer, but rather due to immune activation at the fetal/maternal interface. Elevated percentages of cord blood switched memory B cells were positively associated with 12-month HiB IgG levels. BAFF concentrations at 6 and 12 months were positively associated with pertussis and HiB IgG levels respectively.

Discussion

Sustained B cell immunity is highly influenced by early life immune dynamics beginning prior to birth. The findings provide important insights into how germinal center development shapes vaccine responses in healthy infants and provide a foundation for studies of conditions that impair infant immune development.