Dissociation of efficacy and cytokine release mediated by an Fc-modified anti-CD3 mAb in a chronic experimental autoimmune encephalomyelitis model

The Immunogenicity of Branded and Biosimilar Infliximab in Rheumatoid Arthritis According to Th9-Related Responses

Our objective was to evaluate the immunogenicity of branded and biosimilar infliximab by detecting changes in T-helper-9 (Th9) percentages induced by an in vitro stimulation test.

METHODS

Peripheral blood mononuclear cells collected from 55 consecutive rheumatoid arthritis (RA) outpatients (15 drug free, 20 successfully treated with branded infliximab, 20 branded infliximab inadequate responders) and 10 healthy controls were cultured, with or without 50 μg/mL of infliximab originator (Remicade^®) or 50 μg/mL of infliximab biosimilar (Remsima^®) for 18 h. Th9 lymphocytes were identified by means of flow cytometry as PU.1 and IRF4-expressing, IL-9-secreting CD4⁺ T cells. Furthermore, the markers CCR7 and CD45RA were used to distinguish naïve from memory IL-9 producer cells.

RESULTS

Under unstimulated conditions, the drug-free RA patients had the highest percentages of Th9 lymphocytes. Following stimulation with branded infliximab, the percentages of PU.1 and IRF4-expressing Th9 cells, CCR7⁺, CD45RA^- (central memory) and CCR7^-, CD45RA^- (effector memory) cells significantly increased in the group of inadequate responders, but no significant variation was observed after exposure to the biosimilar of infliximab.

CONCLUSIONS

Th9 cells seem to be involved in the immune response to the epitopes of branded, but not biosimilar, infliximab, and this may depend on the recall and stimulation of both central and effector memory cells.

Therapeutic anti-CD3 monoclonal antibodies: from bench to bedside

The induction of tolerance is a major goal of immunotherapy. Investigations over the last 20 years have shown that anti-CD3 monoclonal antibodies (mAbs) effectively treat autoimmune disease in animal models and have also shown promise in clinical trials. Tolerance induction by anti-CD3 mAbs is related to the induction of Tregs that control pathogenic autoimmune responses. Here, we review preclinical and clinical studies in which intravenous or mucosal administration of anti-CD3 mAbs has been employed and provide an outlook on future developments to enhance the efficacy of this promising therapeutic approach.

Paradoxical Expansion of Th1 and Th17 Lymphocytes in Rheumatoid Arthritis Following Infliximab Treatment: a Possible Explanation for a Lack of Clinical Response

PURPOSE

The immunogenicity of anti-TNF-α drugs may affect their safety and efficacy. Infliximab (IFX), a chimeric monoclonal antibody, induces antibody formation in up to 60% of cases. Some studies have suggested the involvement of a Th1 response to TNFα blockers following immunization, but the triggering of Th17 responses has never been reported. The aim of this study is to investigate whether the immunogenicity of IFX affects the Th1, Th17 and Treg compartments in rheumatoid arthritis (RA) patients failing IFX therapy, and verify whether this may be responsible for treatment failure.

METHODS

The study involved 55 patients with RA (15 treatment-naïve patients; 20 IFX responders; 20 IFX non-responders) and 10 healthy controls. PBMCs were cultured in the presence/absence of IFX, and the variations in the percentage of Th1, Th17 and Treg lymphocytes following IFX treatment were analysed.

RESULTS

IFX-specific Th1 and Th17 responses and an increase in IL-21 production were observed in patients failing IFX (p < 0.01, p < 0.05, and p < 0.01 respectively). In contrast, IFX incubation reduced significantly Th1 and Th17 responses and IL-21 production (p < 0.05) in successfully-treated subjects, but did not affect these responses in healthy controls or treatment-naïve patients.

CONCLUSIONS

RA patients may have impaired peripheral tolerance, which could favour the development of an aberrant immunological response to biological drugs. The loss of therapeutic effectiveness of IFX and the onset of adverse events may be due to a paradoxical activation of Th17 or Th1 lymphocytes following sensitisation, thus worsening the patients' inflammatory status.

A CD3-specific antibody reduces cytokine production and alters phosphoprotein profiles in intestinal tissues from patients with inflammatory bowel disease

BACKGROUND & AIMS

T cells mediate the development of inflammation in inflammatory bowel disease (IBD). We investigated the effects of an antibody against CD3 called otelixizumab, which induces immune tolerance, in intestinal mucosa samples from patients.

METHODS

Intestinal tissues were isolated from patients undergoing routine endoscopy or from patients undergoing intestinal surgery for colon cancer or IBD; healthy surrounding tissues were collected as controls. Isolated lamina propria mononuclear cells (LPMCs) and mucosal tissue explants were incubated with otelixizumab for 24 or 48 hours. Production of inflammatory cytokines was determined by enzyme-linked immunosorbent assay. Levels of 36 cytokines and chemokines and phosphorylation of 39 receptor tyrosine kinases and signaling molecules were measured using protein arrays. Immunoblot analysis was used to analyze T-cell transcription factors.

RESULTS

Incubation of intestinal tissues or LPMCs with otelixizumab reduced production of interferon gamma, interleukin (IL)-17A, and other inflammatory cytokines and chemokines, simultaneously increasing production of IL-10. Mucosal biopsy specimens from patients with IBD retained inflammation-associated tyrosine phosphoprotein profiles ex vivo. Incubation of the inflamed tissue with otelixizumab reduced phosphorylation of these proteins to levels observed in control tissues. Otelixizumab also markedly reduced phosphorylation of proteins associated with T-cell receptor activation. Neutralization of IL-10 blocked the anti-inflammatory effects of otelixizumab.

CONCLUSIONS

We observed anti-inflammatory effects of anti-CD3 in inflamed intestinal tissues from patients with IBD. The antibody appears to down-regulate T-cell activation via IL-10.

The immunogenicity of humanized and fully human antibodies: residual immunogenicity resides in the CDR regions

Monoclonal antibodies represent an attractive therapeutic tool as they are highly specific for their targets, convey effector functions and enjoy robust manufacturing procedures. Humanization of murine monoclonal antibodies has vastly improved their in vivo tolerability. Humanization, the replacement of mouse constant regions and V framework regions for human sequences, results in a significantly less immunogenic product. However, some humanized and even fully human sequence-derived antibody molecules still carry immunological risk. To more fully understand the immunologic potential of humanized and human antibodies, we analyzed CD4(+) helper T cell epitopes in a set of eight humanized antibodies. The antibodies studied represented a number of different VH and VL family members carrying unique CDR regions. In spite of these differences, CD4(+) T cell epitopes were found only in CDR-sequence containing regions. We were able to incorporate up to two amino acid modifications in a single epitope that reduced the immunogenic potential while retaining full biologic function. We propose that immunogenicity will always be present in some antibody molecules due to the nature of the antigen-specific combining sites. A consequence of this result is modifications to reduce immunogenicity will be centered on the affinity-determining regions. Modifications to CDR regions can be designed that reduce the immunogenic potential while maintaining the bioactivity of the antibody molecule.