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D McKinney

Publications and source records attributed to D McKinney.

16 recordsLinked to original sources
PubMed2002

Optimizing vaccine design for cellular processing, MHC binding and TCR recognition.

In this review we describe the methods and processes that our group have developed while aiming to test and design multiepitope vaccines for infectious diseases and cancer. Testing the performance of vaccines composed of epitopes restricted by human leukocyte antigen (HLA) molecules is accomplished by in vitro antigenicity assays, as well as in vivo immunogenicity assays in HLA transgenics. The efficiency by which multiepitope vaccines are processed is optimized by spacer residues, which are designed to facilitate generation by natural processing of the various class I- and class II-restricted epitopes. Methods and strategies to test and optimize HLA binding affinity, patient coverage from the vaccine construct, and TCR recognition of HLA/epitope complexes are also discussed.

Epitopes↗
PubMed2001

Optimization of epitope processing enhances immunogenicity of multiepitope DNA vaccines.

Experimental DNA vaccines comprised of multiple minimal cytotoxic T lymphocytes (CTL) epitopes can effectively induce broad CTL responses; however, such constructs frequently exhibit significant variation in epitope immunogenicity. Antigenicity assays utilizing human cells transfected with one such multiepitope construct revealed that the epitopes with poor immunogenicity were inefficiently processed in transfected cells. Compilation of a database of 94 epitope/flanking region combinations, for which immunogenicity was measured experimentally, revealed that the type of residue immediately following the carboxyl-terminus of the epitope exerted a prominent effect on immunogenicity. Experiments utilizing a variety of HBV-specific vaccine constructs demonstrated epitope immunogenicity could be modulated by the insertion of a single amino acid and the effect on immunogenicity could be ascribed to modulation of processing efficiency. These findings demonstrate that multiepitope DNA vaccines can be engineered to enhance CTL immunogenicity by increasing processing efficiency.

AIDS Vaccines↗
PubMed2001

Digoxin withdrawal in patients with dilated cardiomyopathy following normalization of ejection fraction with beta blockers.

BACKGROUND: The effect of withdrawal of digoxin on left ventricular function in patients with a history of idiopathic dilated cardiomyopathy (IDCM) following normalization of left ventricular ejection fraction (LVEF) with beta blockers remains unknown. HYPOTHESIS: This study was undertaken to determine the effect of digoxin withdrawal on left ventricular function in patients with IDCM. METHODS: In 8 consecutive patients with IDCM (5 men, 3 women) who had normalization of LVEF following beta-blocker treatment, digoxin was withdrawn as part of an office protocol. and LVEF was followed. Baseline EF prior to beta blocker initiation (carvedilol = 6, atenolol = 1, metoprolol 1) was measured with isotope ventriculography (IVG), echocardiography, or left ventriculography. Post beta blocker ejection fraction (post BB EF) was measured in all patients with IVG at a mean of 17.25 +/- 5.38 months. Follow-up EF was measured using IVG after digoxin withdrawal at a mean of 6.99 +/- 4.34 months. RESULTS: An experienced blinded reader interpreted the IVG scans. Baseline EF was 28.5 +/- 8.26; post BB EF and follow-up EF were 56.1 +/- 4.65 and 51.0 +/- 7.35, respectively (p = 0.05). CONCLUSION: These data provide potential evidence that digoxin withdrawal can result in a small but significant reduction in LVEF in patients with IDCM who had normalization of LVEF after treatment with beta blockers. Mean LVEF, however, remained within normal (> 50%) on beta-blocker therapy and without digitalis. Large, randomized controlled trials are needed to confirm these findings.

Adrenergic beta-Antagonists↗
PubMed2001

The outcome of hepatitis C virus infection is predicted by escape mutations in epitopes targeted by cytotoxic T lymphocytes.

CD8(+) cytotoxic T lymphocytes (CTL) are thought to control hepatitis C virus (HCV) replication and so we investigated why this response fails in persistently infected individuals. The HCV quasispecies in three persistently infected chimpanzees acquired mutations in multiple epitopes that impaired class I MHC binding and/or CTL recognition. Most escape mutations appeared during acute infection and remained fixed in the quasispecies for years without further diversification. A statistically significant increase in the amino acid replacement rate was observed in epitopes versus adjacent regions of HCV proteins. In contrast, most epitopes were intact when hepatitis C resolved spontaneously. We conclude that CTL exert positive selection pressure against the HCV quasispecies and the outcome of infection is predicted by mutations in class I MHC restricted epitopes.

Acute Disease↗
PubMed2001

Aminophylline does not protect against radiocontrast nephropathy in patients undergoing percutaneous angiographic procedures.

BACKGROUND: Radiocontrast nephropathy (RCN) is one of the leading causes of hospital-acquired acute renal insufficiency. Adenosine, a renal vasoconstrictor, is thought to play a role in RCN. In this study, aminophylline, a non-selective adenosine-competitive inhibitor, was evaluated as a potential agent to protect against RCN. METHODS: Twenty-six patients treated with 200 mg intravenous aminophylline immediately prior to percutaneous coronary and peripheral procedures were individually matched to 26 controls for baseline creatinine (Cr), diabetes mellitus and amount of contrast used. The aminophylline-treated group was also similar to control with respect to baseline ejection fraction, amount of post-procedure hydration, age, blood pressure and the use of nephrotic drugs. RESULTS: There was no significant difference between the change from baseline Cr to peak measured Cr in either cases or controls. Also, when a change in Cr > or =25% from baseline was considered significant, Fisher's exact test did not show a difference between the 2 groups. CONCLUSION: Aminophylline does not appear to add a protective role in preventing against RCN in patients undergoing percutaneous angiographic procedures.

Aged↗
PubMed1996

H-2Ld-alloreactive T cell hybridomas utilize diverse V alpha and V beta T cell receptor chains.

We have sequenced the TCRs from Ld-specific alloreactive T cell hybridomas, whose reactivities we have found to be quite representative of those of a primary dm2 anti-BALB/cJ mixed lymphocyte reaction. We find V beta 6, V beta 7, V beta 8 and V beta 10 gene segments. V alpha usage is diverse, although closely related to that from peptide-specific Ld-restricted CTLs. V alpha-V beta selection provides evidence of preferential pairing. Amino acid frequency analysis shows that the alpha CDR2 region is rich in charged amino acids, in contrast to the beta CDR2 region. Our data suggests the beta chain may be more immunoglobulin-like than the alpha chain, and that charge complementarity may be important in TCR-MHC interactions. We do not consider our results to be contradictory to those previously reported but rather they may represent an early, more diverse response.

Amino Acid Sequence↗
PubMed1992

Identification of a mammalian gene structurally and functionally related to the CDC25 gene of Saccharomyces cerevisiae.

The yeast Saccharomyces cerevisiae CDC25 gene encodes a nucleotide-exchange-factor (NEF) that can convert the inactive GDP-bound state of RAS proteins to an active RAS-GTP complex. CDC25 can activate the yeast RAS proteins as well as the human H-ras protein. CDC25 is a member of a family of yeast genes that likely encode NEFs capable of regulating the RAS-related proteins found in yeast. By aligning the amino acid sequence of CDC25-related gene products we found a number of conserved motifs. Using degenerate oligonucleotides that encode these conserved sequences, we have used polymerase chain reactions to amplify fragments of mouse and human cDNAs related to the yeast CDC25 gene. We show that a chimeric molecule, part mouse and part yeast CDC25, can suppress the loss of CDC25 function in the yeast S. cerevisiae.

Amino Acid Sequence↗
PubMed1989

The association of H-2Ld with human beta-2 microglobulin induces localized conformational changes in the alpha-1 and -2 superdomain.

We have analyzed changes in the antigenicity of major histocompatibility complex class I molecules resulting from the association of human beta-2 micro-globulin (B2m) with the mouse class I heavy chain. In particular, the H-2Ld molecule exhibited enhanced cross-reactivity for the 34-1-2 monoclonal antibody. In order to assess the nature of this structural alteration induced by human B2m, we utilized H-2 class I hybrid molecules in the mapping of the 34-1-2 determinant to the helical region of the alpha-1 domain. H-2Ld class I hybrid molecules were then used to establish the importance of the alpha-2 and -3 domains in the observed increase of 34-1-2 cross-reactivity following exchange with human B2m. The H-2Ld hybrids suggest that alterations in interdomain contact are responsible for enhanced 34-1-2 cross-reactivity on the H-2Ld molecule. It is likely that this alteration arises through changes in class I conformation at regions of the molecule distant from points of contact between B2m and the class I molecule. This suggests that perturbations induced by association of human B2m with H-2Ld can affect the conformation of the alpha-1 and -2 superdomain. That class I antigenic determinants are altered by the association of human B2m with mouse class I further suggests that the class I molecule is structurally flexible and may reflect the ability of the class I molecule to bind and present a vast array of disparate peptides to the T-cell receptor.

Amino Acid Sequence↗
PubMedDate not supplied

The development of multi-epitope vaccines: epitope identification, vaccine design and clinical evaluation.

We have developed efficient methods for epitope identification and vaccine design. Our process for epitope selection based on the combined use of motif analyses, binding assays and immunogenicity evaluations is described. We also describe how the projected population coverage and vaccine design can be optimized. Finally, it is discussed how vaccine potency is evaluated by immunogenicity and antigenicity assays.

Epitopes↗
PubMedDate not supplied

Endometrial aspiration studies on Isaacs cell sampler with cytohistologic correlation.

Endometrial aspiration material obtained with the Isaacs cell sampler from 220 patients was studied and correlated with tissue biopsy from 172 of these patients. Of 52 endometrial carcinomas, there were two false-negative readings. In addition, five cases thought to be malignancies by cytologic criteria were not confirmed by histology. Therefore, the endometrial cell sampler showed a specificity of 96.85%, sensitivity of 96.15% and predictive value of 90.90%. Only nine cases of unsatisfactory cellular samples were obtained as compared to 13 cases of insufficient material by dilatation and curettage.

Adenocarcinoma↗