Host and Donor Immune Responses Contribute to Antiviral Effects of Amotosalen-Treated Donor Lymphocytes following Early Posttransplant Cytomegalovirus Infection

Abstract

We have previously shown that amotosalen-treated splenocytes rescued allorecipients from a lethal dose of mouse CMV (MCMV) administered on day 0 in experimental parent C57BL/6→CB6F1 allogeneic bone marrow transplant. In this study, we investigated the mechanism of antiviral activity of amotosalen-treated donor splenocytes when sublethal MCMV infections were administered 7 days posttransplant. Recipients of 3 × 106 untreated splenocytes were used as control. Following MCMV infection, recipients of untreated splenocytes had 40% early mortality due to acute graft-vs-host disease compared with no deaths among recipients of 10 × 106 treated splenocytes. However, recipients of both types of donor splenocytes effectively cleared MCMV from their liver. Like the untreated CD8+ T cells, amotosalen-treated CD8+ T cells equally retained their in vivo CTL activity against MCMV early peptide-pulsed targets and expressed similar levels of granzyme B within 11 days of infection. In contrast to full donor chimerism in recipients of untreated splenocytes, recipients of amotosalen-treated splenocytes showed mixed chimerism with both donor spleen- and host-derived anti-MCMV CD8+ T cells in their blood and lymphoid organs, with significantly higher numbers of host-derived CD4−CD8− (double negative) T cells in the spleens of recipients of treated splenocytes compared with the recipients of untreated splenocytes. Additionally, recipients of amotosalen-treated splenocytes had lower levels of serum IFN-γ and TNF-α in response to MCMV infection compared with untreated recipients. Thus, adoptive immunotherapy with treated T cells is a novel therapeutic approach that facilitates hematopoietic engraftment and permits antiviral immunity of both donor and host T cells without graft-vs-host disease.

Pharmacological inhibition of VIP signaling enhances antiviral immunity and improves survival in murine cytomegalovirus-infected allogeneic bone marrow transplant recipients

“…BMT recipients were treated with 7 daily subcutaneous injections of VIPhyb (10 mg per 100 mL per mouse) starting the day prior to intraperitoneal injection of 5 3 10 3 , 1 3 10 4 , 2 3 10 4 , or 1 3 10 5 plaque-forming unit (PFU) of the Smith mCMV strain. 14,15 Mice were monitored daily for survival and clinical signs of GVHD, including posture, activity, diarrhea, fur, and weight. 16 Other methods are addressed in the supplemental Methods section.…”

Absence of Vasoactive Intestinal Peptide Expression in Hematopoietic Cells Enhances Th1 Polarization and Antiviral Immunity in Mice

“…The Smith strain of mCMV passaged in vivo in salivary glands and frozen in aliquots in liquid nitrogen (37, 39). WT and VIP-KO mice, as well as chimeric mice with hematopoietic cells from WT and VIP-KO donors, were given either 5 × 10 4 (LD10; low dose) or 1 × 10 5 (LD 50; high dose) plaque-forming unit (PFU) mCMV by intraperitoneal injection and then monitored for signs of illness including hunched posture, decreased activity, and weight loss.…”

“…We hypothesized that mice lacking VIP expression would show an increased response to viral infection due to a lack of immunosuppressive counter-regulatory activity from DCs. We challenged VIP-KO mice and radiation chimeras engrafted with VIP-KO hematopoietic cells with two sources of mCMV antigen: a Listeria monocytogenes vaccine that expresses an immuno-dominant CMV peptide (Lm-MCMV vaccine)(37, 38), and an infectious strain of mCMV (37, 39). Our results demonstrate that VIP-KO mice and recipients engrafted with VIP-KO hematopoietic cells have augmented cellular immune responses to mCMV antigen, and improved survival after viral infection.…”

PKCθ is required for alloreactivity and GVHD but not for immune responses toward leukemia and infection in mice

“…injection. 3 or 10 days later, mice were sacrificed and livers and spleens obtained to determine virus titer and MCMV-specific tetramer-positive CD8 T cells, respectively, as described previously (44,45).…”

“…How absence of PKCθ has an impact on responses against infectious agents following BMT is not clear. To this end, we used an MCMV infection model (44,45). CMV is one of the most common infections in BMT patients (46) and thus a highly relevant infectious agent for these studies.…”