An in vivo animal model of gene therapy for leukocyte adhesion deficiency.

Abstract

Leukocyte adhesion deficiency (LAD) is an inherited disorder of leukocyte function that is caused by defects in the CD18 gene and is associated with diminished cell surface expression of CD11/CD18 proteins. We have developed an in vivo model for gene therapy of LAD. Recombinant retroviruses were used to transduce a functional human CD18 gene into murine bone marrow cells which were transplanted into lethally irradiated syngeneic recipients. A reliable flow cytometric assay for human CD18 in transplant recipients was developed based on: (a) the availability of human specific CD18 monoclonal antibodies and (b) the observation that human CD18 can form chimeric heterodimers with murine CD11a on the cell surface. Human CD18 was detected on leukocytes in a substantial number of transplant recipients for at least 6 mo suggesting that the gene had been transduced into stem cells. Expression was demonstrated in several lineages of a variety of hematopoietic tissues, but was consistently highest and most frequent in granulocytes. Murine granulocytes demonstrated appropriate posttranscriptional regulation of human CD18 in response to activation of protein kinase C. No apparent untoward effects of human CD18 expression were noted in transplant recipients. These studies suggest a specific strategy for LAD gene therapy that may be effective and safe.

Lentiviral Vector-Mediated Correction of a Mouse Model of Leukocyte Adhesion Deficiency Type I

“…Our data in the CD18 HYP mouse model are consistent with previous studies showing that hCD18 can be expressed in the membrane of murine cells coupled to its mCD11 counterpart, indicating that both human and murine CD18 subunits might function similarly in a mouse environment. 8 , 10 , 40 Our data additionally show that neutrophils derived from transduced CD18 HYP lin − cells are able to upregulate hCD18 expression upon PMA stimulation. Moreover, when methylcellulose-based colony-forming cell assays were performed, no differences in the number of CFUs were observed among untransduced, GFP-transduced, or hCD18-transduced cells, indicating that neither the LV transduction nor the ectopic expression of hCD18 mediates significant hematopoietic toxicity.…”

A Missense Mutation in the β-2 Integrin Gene (ITGB2) Causes Canine Leukocyte Adhesion Deficiency

“…Previous work indicated that human CD18 could form cross-species heterodimers with mouse CD11 (Krauss et al, 1991) and baboon CD11 (Bauer et al, 1996). Therefore, it was predicted that canine CD18 would heterodimerize with human CD11 and complement the CD18 defect in LAD EBV B-cells.…”

The Association of Leukocyte Adhesion Defect Type I and Persistent Hyperinsulinemic Hypoglycemia of Infancy in a Saudi Arabian Family

“…This was done successfully in the 2 patients discussed, and sibling cord blood transfusion was successful [11]. Gene therapy has been proposed as a treatment for these patients [12,13].…”