Involvement of spinal calcitonin gene-related peptide in the development of acute visceral hyperalgesia in the rat.

This study aimed to characterize the role of the neuropeptide calcitonin gene-related peptide (CGRP) in the development of mechanically induced visceral hyperalgesia. Tonic colorectal distension (CRD) was performed in fasted, conscious male Sprague-Dawley rats. The visceromotor reflex associated with noxious CRD was determined as the number of contractions during each of two consecutive tonic distensions (10 min at 60 mmHg), which were separated by a series of phasic distensions (repeated 15-s distensions to 80 mmHg at 30-s intervals). The effect of the CGRP receptor antagonist h-CGRP8-37 given intrathecally (i.t.) (0.03-3 nmol rat-1) or intravenously (i.v.) (20 microg kg-1 bodyweight [bw]) on the visceromotor response was evaluated. The dose for i.v. administration was chosen based on previous results from similar studies. In addition, the effect of a CGRP monoclonal antibody (6 mg kg-1 bw) given intravenously was evaluated. Compared to the baseline response, a significant increase in the number of abdominal contractions was observed during the second tonic distension. The i.t. application of h-CGRP8-37 dose-dependently reduced the numbers of abdominal contractions both during the first and the second tonic distension period, with a maximum effect observed at a peptide concentration of 3 nmol. Intravenous administration of h-CGRP8-37 or of the CGRP antiserum produced a small reduction of the visceromotor response induced by the second tonic distension and had no effect on colonic compliance. The development of mechanically induced colorectal hyperalgesia by repeated tonic distension involves the spinal release of CGRP, while peripheral release of CGRP plays only a minor role.

CD3xCD19 bispecific antibodies and CD28 bivalent antibodies enhance T-cell reactivity against autologous leukemic cells in pediatric B-ALL bone marrow.

Bispecific CD3xCD19 antibodies and CD28 co-stimulating antibodies were used to activate T cells in bone marrow aspirates (n = 8) of children with B cell-derived acute lymphoblastic leukemia. Bone marrow specimens were incubated for 10 days with CD3xCD19 bispecific and CD28 antibodies. Changes in the numbers of T lymphocytes and tumoral B cells as well as surface expression of T cell-activation markers were determined by flow cytometry, and cytokines (human IFN-gamma, IL-2, IL-4 and IL-12) were measured in the cell culture supernatant. In 7 of 8 bone marrow samples, an increase in the number of CD4- and CD8-positive T lymphocytes was found, which correlated with an up-regulation of T cell-activation markers. Additionally, we demonstrated a decrease of tumoral B cells in 3 samples and enhanced cytotoxic T-cell activity against autologous malignant B cells. ELISpot analyses in an autologous Epstein-Barr virus model showed that bispecific antibodies (CD3xCD19+CD28) were more potent at generating T-cell responses against autologous and allogeneic tumoral targets than a combination of monospecific antibodies (CD3+CD28). Thus, T-cell targeting by CD3xCD19 bispecific and CD28 antibodies may be used to eliminate leukemic B cells ex vivo and reconstitute immunological control of residual malignant disease by the induction of anti-tumoral T-cell responses.