Recent studies have shown that CD32/CD8a/CD28/CD3ζ chimeric receptor cells directly kill breast cancer cells, suggesting the existence of cell surface myeloid FcγR alternative ligands (ALs). Here, we investigated the metabolism, ALs, cytotoxicity, and immunoregulatory functions of CD64/CD28/CD3ζ in colorectal cancer (CRC) and squamous cell carcinoma of the head and neck.
The CD64/CD28/CD3ζ -SFG retroviral vector was used to produce viruses for T-cell transduction. T-cell expansion and differentiation were monitored via flow cytometry. Gene expression was assessed by RNA-seq. Bioenergetics were documented on a Seahorse extracellular flux analyzer. CD64/CD28/CD3ζ polarization was identified via confocal microscopy. Cytotoxicity was determined by MTT assay and bioluminescent imaging, and flow cytometry. Tridimensional antitumor activity of CD64/CD28/CD3ζ T cells was achieved by utilizing HCT116-GFP 3D spheroids via the IncuCyte S3 Live-Cell Analysis system. The intraperitoneal distribution and antitumor activity of NIR-CD64/CD28/CD3ζ and NIR-nontransduced T cells were investigated in CB17-SCID mice bearing subcutaneous FaDu Luc + cells by bioluminescent and fluorescent imaging. IFNγ was assessed by ELISA.
Compared to CD16/CD8a/CD28/CD3ζ T cells, CD32/CD8a/CD28/CD3ζ T cells, and non-transduced T cells, CD64/CD28/CD3ζ T cells exhibited the highest levels of cell expansion and persistence capacity. A total of 235 genes linked to cell division and 52 genes related to glycolysis were overexpressed. The glycolytic phenotype was confirmed by functional in vitro studies accompanied by preferential T-cell effector memory differentiation. Interestingly, oxamic acid was found to inhibit CD64-CR T cell proliferation, indicating the involvement of lactate. Upon CD64/CD28/CD3ζ T-cell conjugation with CRC cells, CD64/CD28/CD3ζ cells polarize at immunological synapses, leading to CRC cell death. CD64/CD28/CD3ζ T cells kill SCCHN cells, and in combination with the anti-B7-H3 mAb (376.96) or anti-EGFR mAb, these cells trigger antibody-dependent cellular cytotoxicity (ADCC) in vitro under 2D and 3D conditions. The 376.96 mAb combined with CD64/CD28/CD3ζ T cells had anti-SCCHN activity in vivo. In addition, they induce the upregulation of PD-L1 and HLA-DR expression in cancer cells via IFNγ. PD-L1 positive SCCHN cells in combination with anti-PD-L1 mAb and CD64-CR T cells were killed by ADCC, which enhanced direct cytotoxicity. These findings indicate that the glycolytic phenotype is involved in CD64-CR T cell proliferation/expansion. These cells mediate long-lasting HLA-independent cytotoxicity and ADCC in CRC and SCCHN cells.
CD64/CD28/CD3ζ T cells could significantly impact the rational design of personalized studies to treat CRC and SCCHN and the identification of novel FcγR ALs in cancer and healthy cells.
© 2025. The Author(s).

Previous research showed that the intracellular complement system, with CD46 as its central molecule, regulates the Th1 response associated with IFN-γ production and transition to a type 1 regulatory response (Tr1) characterized by IL-10 production. This transition can be influenced by a vitamin D (calcitriol), favouring a shift towards Tr1 cells and increased IL-10 production, as described in some autoimmune diseases.
It is unknown whether calcitriol modulates CD46-induced Th1 response towards regulatory type 1 T cells (Tr1) in allergic eosinophilic asthma and its value in relation to reducing inflammatory response.
CD4+ T cells from 58 patients with allergic eosinophilic asthma (AEA) and 49 healthy donors (HDs) were stimulated with αCD3/αCD46/IL-2 or αCD3/αCD46/IL-2/Calcitriol in vitro for 60 h and analyzed by flow cytometry. IFN-γ and IL-10 levels in cell culture supernatants were measured using ELISA.
CD4+ T cells from patients with AEA demonstrated elevated CD46 expression in both the non-activated state and under stimulation conditions with αCD3/αCD46/IL-2 or αCD3/αCD46/IL-2/Calcitriol. Moreover, CD46 expression in AEA patients fluctuated with the pollen season, showing a significant increase during period of low pollen exposure. Calcitriol further induced CD4+Tr1 cells from in vitro generated CD4+Th1 cells in both HDs and AEA patients. However, in both cohorts were individuals (HDs: 35/49, AEA: 40/58) who responded to calcitriol with a more pronounced regulatory response. The calcitriol-induced regulatory effect manifested by a stronger surface decrease of CD46 on activated CD4+ T cells (by 40% in HDs and by 26% in AEA), accompanied by a significant inhibition of IFN-γ and increased IL-10 production (by 31% in HDs and by 85% in AEA). These individuals were termed as the CD46D group. Contrary to this, calcitriol induced an increase in CD46 expression at the CD4+ T cell surface in a minor group of HDs (14/49), and AEA patients (18/58), who were termed as the CD46I group. In CD46I group, CD4+ T cells produced less IFN-γ in comparison with CD46D group (by 33% in HDs and by 43% in AEA) and were unable to upregulate IL-10 production following stimulation with αCD3/αCD46/IL-2/Calcitriol.
Our results suggest the potential existence of a key for stratifying individuals suitable for calcitriol treatment in the context of low serum vitamin D levels. After validation in clinical studies, this key could be used as an adjunctive therapy not only for patients with allergic eosinophilic asthma, but also for other diseases.
© 2024 Stichova, Slanina, Chovancova, Baros, Litzman, Litzman and Vlkova.

Immune-mediated arthritis is a group of autoinflammatory diseases, where the patient's own immune system attacks and destroys synovial joints. Sustained remission is not always achieved with available immunosuppressive treatments, warranting more detailed studies of T cell responses that perpetuate synovial inflammation in treatment-refractory patients.
In this study, we investigated CD4 + and CD8 + T lymphocytes from the synovial tissue and peripheral blood of patients with treatment-resistant immune-mediated arthritis using paired single-cell RNA and TCR-sequencing. To gain insights into the trafficking of clonal families, we compared the phenotypes of clones with the exact same TCRß amino acid sequence between the two tissues.
Our results show that both CD4 + and CD8 + T cells display a more activated and inflamed phenotype in the synovial tissue compared to peripheral blood both at the population level and within individual T cell families. Furthermore, we found that both cell subtypes exhibited clonal expansion in the synovial tissue.
Our findings suggest that the local environment in the synovium drives the proliferation of activated cytotoxic T cells, and both CD4 + and CD8 + T cells may contribute to tissue destruction and disease pathogenesis.
© 2024. The Author(s).

Vaccines are highly effective tools against infectious diseases and are also considered necessary in the fight against malaria. Vaccine-induced immunity is frequently mediated by antibodies. We have recently conducted a first-in-human clinical trial featuring SumayaVac-1, a malaria vaccine based on the recombinant, full-length merozoite surface protein 1 (MSP1FL) formulated with GLA-SE as an adjuvant. Vaccination with MSP1FL was safe and elicited sustainable IgG antibody titers that exceeded those observed in semi-immune populations from Africa. Moreover, IgG antibodies stimulated various Fc-mediated effector mechanisms associated with protection against malaria. However, these functionalities gradually waned. Here, we show that the initial two doses of SumayaVac-1 primarily induced the cytophilic subclasses IgG1 and IgG3. Unexpectedly, a shift in the IgG subclass composition occurred following the third and fourth vaccinations. Specifically, there was a progressive transition to IgG4 antibodies, which displayed a reduced capacity to engage in Fc-mediated effector functions and also exhibited increased avidity. In summary, our analysis of antibody responses to MSP1FL vaccination unveils a temporal shift towards noninflammatory IgG4 antibodies. These findings underscore the importance of considering the impact of IgG subclass composition on vaccine-induced immunity, particularly concerning Fc-mediated effector functions. This knowledge is pivotal in guiding the design of optimal vaccination strategies against malaria, informing decision making for future endeavors in this critical field.

Many whey proteins, peptides and protein-derived amino acids have been suggested to improve gut health through their anti-oxidant, anti-microbial, barrier-protective and immune-modulating effects. Interestingly, although the degree of hydrolysis influences peptide composition and, thereby, biological function, this important aspect is often overlooked. In the current study, we aimed to investigate the effects of whey protein fractions with different degrees of enzymatic hydrolysis on the intestinal epithelium in health and disease with a novel 2D human intestinal organoid (HIO) monolayer model. In addition, we aimed to assess the anti-microbial activity and immune effects of the whey protein fractions. Human intestinal organoids were cultured from adult small intestines, and a model enabling apical administration of nutritional components during hypoxia-induced intestinal inflammation and normoxia (control) in crypt-like and villus-like HIO was established. Subsequently, the potential beneficial effects of whey protein isolate (WPI) and two whey protein hydrolysates with a 27.7% degree of hydrolysis (DH28) and a 50.9% degree of hydrolysis (DH51) were assessed. In addition, possible immune modulatory effects on human peripheral immune cells and anti-microbial activity on four microbial strains of the whey protein fractions were investigated. Exposure to DH28 prevented paracellular barrier loss of crypt-like HIO following hypoxia-induced intestinal inflammation with a concomitant decrease in hypoxia inducible factor 1 alpha (HIF1α) mRNA expression. WPI increased Treg numbers and Treg expression of cluster of differentiation 25 (CD25) and CD69 and reduced CD4+ T cell proliferation, whereas no anti-microbial effects were observed. The observed biological effects were differentially mediated by diverse whey protein fractions, indicating that (degree of) hydrolysis influences their biological effects. Moreover, these new insights may provide opportunities to improve immune tolerance and promote intestinal health.