Immune effects of resuscitation with HBOC-201, a hemoglobin-based oxygen carrier, in swine with moderately severe hemorrhagic shock from controlled hemorrhage.

HBOC-201, a hemoglobin-based oxygen carrier, improved physiologic parameters and survival in hemorrhagic shock (HS) animal models. However, resuscitation from HS and the properties of different fluids influence immune responses. The aim of this study was to determine if HBOC-201 significantly alters immune function in traumatic HS. Anesthetized pigs underwent soft tissue injury, controlled hemorrhage of 40% of blood volume, and resuscitation with HBOC-201 or Hextend, or no resuscitation. Sequential whole-blood samples were collected for analyses of leukocyte differential (hematology analyzer), T-lymphocyte subsets (CD3, CD4, and CD8) (FACS), lymphocyte adhesion marker CD49d (alpha4-integrin) expression (FACS), plasma cytokines-tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-10-(ELISA), and lymphocyte apoptosis (annexin-V/propidium iodide staining) (FACS). Statistical analyses were performed by the mixed procedure. Total WBC counts decreased posthemorrhage in both resuscitation groups. Lymphocyte percentages decreased and PMN percentages increased around 4 h posthemorrhage in all groups. CD3 cells decreased in all groups, but CD4 and CD8 cells decreased only in the resuscitation groups. TNF-alpha levels were not detectable in any groups. IL-6 levels were similar across treatment groups (P > 0.05); however, IL-10 levels were higher in the HBOC group, as early as 1 h posthemorrhage (P = 0.04). Increases in lymphocytic CD49d expression levels and apoptosis occurred only in nonresuscitation and Hextend groups, respectively (P < or = 0.01). In comparison with Hextend, HBOC-201 had no significant adverse or beneficial effects on immune function in this model of moderately severe HS in swine, suggesting that it may be safe as a resuscitation fluid in HS patients.

Human dendritic cells genetically engineered to express cytosolically retained fragment of prostate-specific membrane antigen prime cytotoxic T-cell responses to multiple epitopes.

The ability of two plasmid DNA vaccines to stimulate lymphocytes from normal human donors and to generate antigen-specific responses is demonstrated. The first vaccine (truncated; tPSMA) encodes for only the extracellular domain of prostate-specific membrane antigen (PSMA). The product, expressed following transfection with this vector, is retained in the cytosol and degraded by the proteasomes. For the "secreted" (sPMSA) vaccine, a signal peptide sequence is added to the expression cassette and the expressed protein is glycosylated and directed to the secretory pathway. Monocyte-derived dendritic cells (DCs) are transiently transfected with either sPSMA or tPSMA plasmids. The DCs are then used to activate autologous lymphocytes in an in vitro model of DNA vaccination. Lymphocytes are boosted following priming with transfected DCs or with peptide-pulsed monocytes. Their reactivity is tested against tumor cells or peptide-pulsed T2 target cells. Both tPSMA DCs and sPSMA DCs generate antigen-specific cytotoxic T-cell responses. The immune response is restricted toward one of the four PSMA-derived epitopes when priming and boosting is performed with sPSMA. In contrast, tPSMA-transfected DCs prime T cells toward several PSMA-derived epitopes. Subsequent repeated boosting with transfected DCs, however, restricts the immune response to a single epitope due to immunodominance.