Intravenous immunoglobulin prevents murine antibody-mediated acute lung injury at the level of neutrophil reactive oxygen species (ROS) production.

Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-associated mortality that can occur with any type of transfusion and is thought to be primarily due to donor antibodies activating pulmonary neutrophils in recipients. Recently, a large prospective case controlled clinical study of cardiac surgery patients demonstrated that despite implementation of male donors, a high incidence of TRALI still occurred and suggested a need for additional interventions in susceptible patient populations. To examine if intravenous immunoglobulin (IVIg) may be effective, a murine model of antibody-mediated acute lung injury that approximates human TRALI was examined. When BALB/c mice were injected with the anti-major histocompatibility complex class I antibody 34-1-2s, mild shock (reduced rectal temperature) and respiratory distress (dyspnea) were observed and pre-treatment of the mice with 2 g/kg IVIg completely prevented these symptoms. To determine IVIg's usefulness to affect severe lung damage, SCID mice, previously shown to be hypersensitive to 34-1-2s were used. SCID mice treated with 34-1-2s underwent severe shock, lung damage (increased wet/dry ratios) and 40% mortality within 2 hours. Treatment with 2 g/kg IVIg 18 hours before 34-1-2s administration completely protected the mice from all adverse events. Treatment with IVIg after symptoms began also reduced lung damage and mortality. While the prophylactic IVIg administration did not affect 34-1-2s-induced pulmonary neutrophil accumulation, bone marrow-derived neutrophils from the IVIg-treated mice displayed no spontaneous ROS production nor could they be stimulated in vitro with fMLP or 34-1-2s. These results suggest that IVIg prevents murine antibody-mediated acute lung injury at the level of neutrophil ROS production and thus, alleviating tissue damage.

Genetic and proteomic analysis of the MHC class I repertoire from four ovine haplotypes.

Immunity to livestock diseases can be studied directly in the target animal, but its elucidation is often constrained by the lack of major histocompatibility complex (MHC)-defined animals. To address this issue, we have established an MHC-defined sheep resource flock generated around four diverse MHC haplotypes. Initial characterisation of the repertoire of transcribed MHC class I genes identified three class I transcripts associated with each haplotype. Nucleotide sequence, transcript abundance and phylogenetic analysis indicated that they represent alleles at up to four polymorphic loci that vary in number between the different haplotypes. The functional significance of each of these genes is evaluated here using complementary molecular genetic and proteomic approaches. We determine which genes give rise to proteins that localise to the surface of transfected cells. In addition, we provide data to support the generation of expressed products, based on immunoprecipitation of class I products from animals homozygous for each of the four MHC haplotypes followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This provides a clearer picture of the number of MHC class I loci in sheep and allows more rational prediction of their classical (class Ia) or non-classical (class Ib) nature. On the basis of the cellular localisation, phylogenetic and transcriptional analyses, we propose that the ovine MHC comprises a minimum of eight class I loci, with considerable variation between haplotypes.