The number of patients awaiting organs for transplantation continues to increase each year, and growing numbers of patients with organ failure die because no organs are available. Xenotransplantation offers a potentially unlimited supply of transplantable organs to meet this clinical need, but no effective regimens yet exist that will safely prevent hyperacute rejection of discordant xenografts. As the first portion of the Physician Scientist Award, the major objective of the proposed phase I research project is for the candidate to receive basic science training and a Ph.D. degree in the field of Immunology at Duke University. As part of the thesis project, the applicant will investigate the mechanism of complement and antibody-mediated hyperacute xenograft rejection in the guinea pig-to-Lewis rat model of discordant xenotransplantation. The first goal will be to establish whether hyperacute rejection is modulated in the neonatally B cell depleted Lewis rat. Next, adult rats will be depleted of B cells using in vivo administration of anti-B cell monoclonal antibodies. Peripheral lymphocyte subsets and xenoreactivity against guinea pig lymphocyte targets will be assessed by flow cytometry throughout these studies. Should these techniques fail to deplete NAbs, plasma exchange or xenogeneic organ perfusion will be utilized in an effort to reduce NAb levels and prolong guinea pig cardiac xenograft survival. The second goal is to evaluate the mechanism of complement activation during hyperacute xenograft rejection. Hemolytic and other assays will be utilized to dissect the nature of complement activation, and in particular the role of C3a and C5a in this process. These peptides will be purified and used to produce rat C3a and C5a specific mouse monoclonal antibodies. These monoclonals will then be used in an attempt to modulate C3a and C5a mediated damage in vivo. Using the mechanistic data derived from these studies, complement inhibitors specific for important steps identified in the hyperacute rejection response will be tested in vivo to prolong guinea pig-toLewis rat cardiac xenograft model. If indicated by these initial studies, therapy directed against both the complement and NAb components of the response will be combined in an effort to further prolong xenograft survival.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Physician Scientist Award (K11)
Project #
5K11AI001092-05
Application #
2886002
Study Section
Allergy & Clinical Immunology-1 (AITC)
Program Officer
Prograis, Lawrence J
Project Start
1992-09-01
Project End
2000-08-31
Budget Start
1999-09-01
Budget End
2000-08-31
Support Year
5
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Duke University
Department
Surgery
Type
Schools of Medicine
DUNS #
071723621
City
Durham
State
NC
Country
United States
Zip Code
27705
Pruitt, S K; Bollinger, R R; Collins, B H et al. (1997) Effect of continuous complement inhibition using soluble complement receptor type 1 on survival of pig-to-primate cardiac xenografts. Transplantation 63:900-2
Pruitt, S k; Bollinger, R R; Collins, B H et al. (1996) Continuous complement (C) inhibition using soluble C receptor type 1 (sCR1): effect on hyperacute rejection (HAR) of pig-to-primate cardiac xenografts. Transplant Proc 28:756
Pruitt, S K; Baldwin 3rd, W M; Sanfilippo, F (1996) The role of C3a and C5a in hyperacute rejection of guinea pig-to-rat cardiac xenografts. Transplant Proc 28:596
Davis, E A; Pruitt, S K; Greene, P S et al. (1996) Inhibition of complement, evoked antibody, and cellular response prevents rejection of pig-to-primate cardiac xenografts. Transplantation 62:1018-23
Baldwin 3rd, W M; Pruitt, S K; Brauer, R B et al. (1995) Complement in organ transplantation. Contributions to inflammation, injury, and rejection. Transplantation 59:797-808
Pruitt, S K; Baldwin 3rd, W M; Barth, R N et al. (1993) The effect of xenoreactive antibody and B cell depletion on hyperacute rejection of guinea pig-to-rat cardiac xenografts. Transplantation 56:1318-24
Brauer, R B; Baldwin 3rd, W M; Daha, M R et al. (1993) Use of C6-deficient rats to evaluate the mechanism of hyperacute rejection of discordant cardiac xenografts. J Immunol 151:7240-8