Engineering chimeric autoantibody receptor T cells for targeted B cell depletion in multiple sclerosis model: An in-vitro study.

Background: Recent evidence suggests that B cells and autoantibodies have a substantial role in the pathogenesis of Multiple sclerosis. T cells could be engineered to express chimeric autoantibody receptors (CAARs), which have an epitope of autoantigens in their extracellular domain acting as bait for trapping autoreactive B cells. This study aims to assess the function of designed CAAR T cells against B cell clones reactive to the myelin basic protein (MBP) autoantigen. Methods: T cells were transduced to express a CAAR consisting of MBP as the extracellular domain. experimental autoimmune encephalomyelitis (EAE) was induced by injecting MBP into mice. The cytotoxicity, proliferation, and cytokine production of the MBP-CAAR T cells were investigated in co-culture with B cells. Results: MBP-CAAR T cells showed higher cytotoxic activity against autoreactive B cells in all effector-to-target ratios compared to Mock T cell (empty vector-transduced T cell) and Un-T cells (un-transduced T cell). In co-cultures containing CAAR T cells, there was more proliferation and inflammatory cytokine release as compared to Un-T and Mock T cell groups. Conclusion: Based on these findings, CAAR T cells are promising for curing or modulating autoimmunity and can be served as a new approach for clone-specific B cell depletion therapy in multiple sclerosis.

Fat1 cadherin provides a novel minimal residual disease marker in acute lymphoblastic leukemia.

Measurement of minimal residual disease (MRD) maintains an important role in the clinical management of acute lymphoblastic leukemia (ALL). Recently, we identified Fat1 cadherin as a unique and independent prognostic factor for relapse-free and overall survival in pediatric pre-B-ALL. Here, we analyzed Fat1 mRNA for its potential as a novel marker of MRD in cases of pre-B- and T-ALL. Analyses of microarray data from 125 matched diagnosis/relapse samples across three independent datasets indicate that Fat1 mRNA is detectable in an average of 31.3% of diagnosed pre-B-ALL, of which 67.5% of cases remained positive at relapse. Furthermore, some 20% of cases with undetectable levels of Fat1 mRNA at diagnosis became positive upon relapse. T-ALL cases were 83.3% positive for Fat1 expression at diagnosis with 77.7% remaining positive at relapse. Towards proof of concept, we developed a quantitative polymerase chain reaction assay and demonstrate detection of Fat1 mRNA in leukemic cells mixed with normal peripheral blood cells at a sensitivity of 1 in 10 000 to 100 000 cells. Fat1 may therefore provide a new marker of MRD for patients with ALL lacking known genomic aberrations or within a multiplex approach to MRD detection.

Effects of neuropeptide substance P on the expression of adhesion molecules in cord blood hematopoietic stem cells.

Modulation of adhesion molecules expression on the surface of cord blood (CB) CD34(+) cells may assist in overcoming the delay in cord blood engraftment. Likewise, utilization of diverse growth factors such as neuropeptides could also be helpful. Therefore, we aimed to assess the role of Substance P (SP) along with a cytokine cocktail on CB CD34(+) adhesion molecule expression. CB CD34(+) cells were cultured in a serum-free media containing different concentrations of SP in combination with a cytokine cocktail (SCF, FL, TPO, IL-3, and IL-6). Expression of adhesion molecules CXCR4, CD44, CD49e, and CD62L was analyzed after 7 and/or 11 days of cell cultivation. Additionally, the colonogenic capacity of cells was analyzed by colony formation unit assay. Our results show an enhanced percentage of CD34(+)cells with CXCR4, CD44, and CD62L on day 7, as compared with control. Furthermore, an increase in frequency was observed for CD49e(+) CD34(+)cells by day 7 in both test and control groups compared with day 0. Colonogenic assays show occurrence of more total colony formation and immature progenitor cells in SP-treated cells. Our study indicates that SP could act as an effective modulator for expression of cell adhesion molecules.

Substance P and calcitonin gene-related neuropeptides as novel growth factors for ex vivo expansion of cord blood CD34(+) hematopoietic stem cells.

There is little evidence on roles of growth factors other than cytokines in expansion of cord blood (CB) stem cells. We aimed to explore a novel approach for expansion, using Substance P (SP) and calcitonin gene-related peptide (CGRP) neuropeptides. CB CD34(+) cells were cultured in different concentrations of SP and/or CGRP in combination with a cytokine cocktail. Phenotypic and functional analysis was performed by flowcytometry and colonogenic assay. Our results show a significant improvement of total expansion of neuropeptide treated cells. There was a selective effect of CGRP on CD34(+) CD133(+) cells, SP on CD34(+) CD45(dim) cells, and 10(- 9) M SP and/or CGRP on expansion of CD34(+) CD38(- ) cells. There was also a tendency for erythroid and granulocyte-myeloid colony formation in SP and CGRP treated cultures, respectively. Supplementation of cytokines with other growth factors, such as neuropeptides, might enable us to overcome the difficulties of ex vivo expansion of CB cells.