Single-step purification of prostatic acid phosphatase: immunoaffinity chromatography with a monoclonal antibody

Proteomic approach for purification of seminal plasma proteins involved in tumor proliferation

Human seminal plasma contains a large array of proteins required for the normal physiology and metabolism of spermatozoa. These are mainly secreted from prostate epithelium, testes, and seminal vesicles. Fortunately, many of these are found to be present at elevated concentration in seminal plasma and act as a biomarker of different carcinomas as their levels are also enhanced in serum and are found to be involved in tumor progression and metastasis apart from fertility. The proteins which were overexpressed in the seminal plasma of prostate carcinoma patients were identified by 2-DE and MALDI-TOF/MS. We have designed a strategy to purify these four proteins prostate specific antigen (PSA), prostatic acid phosphatase (PAP), Zinc alpha2-glycoprotein (ZAG), and progastricsin (PG), together in homogeneity by using simple chromatographic techniques. Acidic and basic fractions of human seminal plasma were separated by ion exchange chromatography and further purified by gel permeation chromatography. Our results form a new and valuable resource for those attempting structure-based drug designing for prostate and other cancers where the amount of proteins is required in plenty and in native form.

Molecular cloning and expression of uroplakins in transitional cell carcinoma

BACKGROUND

Uroplakins (UPs), urothelium-specific transmembrane proteins, are present only in urothelia and may be good candidates as tumor markers specific for transitional cell carcinomas (TCCs). We investigated the expression of UP genes in the tissues and peripheral blood of patients with TCCs.

MATERIALS AND METHODS

We determined the nucleotide sequences of UPs by a polymerase chain reaction (PCR)-based method. We then investigated UP gene expression in tissues from 12 patients with TCC by reverse transcription (RT)-PCR. We also investigated UP gene expression in peripheral blood of 12 other patients with TCC by nested RT-PCR. Polyclonal and monoclonal antibodies against UPs were generated using synthesized polypeptides and recombinant protein, respectively, as immunogens.

RESULTS

We determined the nucleotide sequence of human UP-Ib, UP-II, and UP-III cDNAs and produced gene-specific primer pairs for each and for UP-Ia. UP genes were expressed in both cancerous and non-cancerous urothelia taken from all patients examined (as detected by RT-PCR). The detection sensitivity of our assay system was such that 1 cancer cell could be detected in 5 mL of peripheral blood. UP gene-expression was also detected in the peripheral blood of 3 patients with metastatic TCC, but not from 9 patients with non-metastatic TCC or from 3 healthy volunteers. Antibodies against both UP-Ia and UP-Ib reacted with the cell membrane of TCCs.

CONCLUSIONS

UPs may be employed as tumor markers for TCCs, because they are highly conserved and well expressed in non-cancerous and cancerous cells. Furthermore, detection of UP gene expression in blood by nested RT-PCR may provide helpful information in the diagnosis and management of TCCs. We are currently expanding an immunohistochemical study by targeting a larger number of patients to examine the clinical usefulness of these antibodies.

Antitumor killer lymphocytes in the peripheral blood of a patient with transitional cell carcinoma of the bladder

BACKGROUND

Peripheral blood lymphocytes (PBL) from patients with bladder cancer also contain cells possessing cytotoxic activity against autologous tumor cells. These cells are phenotypically heterogenous and include natural killer (NK) and cytotoxic T cells. This study investigated the role of cytotoxic lymphocytes directed against autologous bladder cancer cells.

METHODS

PBL were obtained at intervals before and after surgery and analyzed for cytotoxic activity against autologous bladder cancer cells in 4-hour 51Cr release assay. PBL stimulated with autologous tumor cells were also transformed with human T-lymphotropic virus type-1, establishing a cell line (KB31) which was analyzed for phenotype and cytotoxic activity against the autologous tumor cells.

RESULTS

PBL preoperative cytotoxic activity was low, but increased after surgery. Cytotoxic activity was found not only against autologous bladder cancer cells, but also against heterologous bladder cancer (KK-47) and myeloid leukemia (K562) cells, with the highest activity against the heterologous cell lines. The cytotoxic activity of KB31 was 40% against autologous tumor cells 6 weeks after initiation of the cell line, but decreased to 5% by 6 months. This activity was lower than that against the other cell lines, and was similar to that of PBL in short-term culture. Fluorescence-activated cell sorter (FACS) analysis demonstrated that in KB31 cells at 6 weeks, CD8+ cells were dominant, but CD56+ cells predominated at 6 months.

CONCLUSION

These results suggest that the presence of cytotoxic activity in the peripheral blood of the patient was due to both cytotoxic T cells and NK cells. The cytotoxic activity was lowest prior to surgery and increased postoperatively.

Molecular nature of a sperm acrosomal antigen recognized by HS-13 monoclonal antibody

Among the numerous monoclonal antibodies generated against human sperm antigens, HS-13 monoclonal antibody was shown to react with an intra-acrosomal antigen from human, mouse and rat. In this study, HS-13 was used as the affinity ligand for the purification of the cognate antigen from human sperm by immunoaffinity chromatography. The purified cognate antigen from human sperm, designated as HSAg-13, was found to be a protein with a molecular weight of approximately 80 kDa on SDS-PAGE in the presence of reducing reagents. This monoclonal antibody was used as the probe to study the tissue distributions and developmental expression of the cognate antigen from human, mouse and rat by immunohistochemical assays. It was concluded that the antigen recognized by HS-13 antibody is highly sperm specific and found only in sperm and mature testis, but not in any other somatic tissues examined in human and mouse. The antigen was shown to be expressed at the postmeiotic stages of spermatogenesis in mouse and rat. By using indirect immunofluorescent staining assay, HS-13 was shown to react only with the methanol-fixed acrosome-intact sperm but not with the live sperm. Following calcium ionophore A23187 treatment, acrosome-reacted sperm showed either negative staining or residual staining in the equatorial region, suggesting the intra-acrosomal location of HSAg-13. The spontaneous acrosome reaction following overnight incubation in BWW medium resulted in a statistically significant decrease of antibody-stained human sperm. In view of excellent correlations for the scoring of acrosome-intact sperm with that of fluorescence-labeled Pisum sativum agglutinin (PSA) probe, HS-13 monoclonal antibody can be routinely used for monitoring sperm capacitation and acrosome reaction.

Purification and characterization of a sperm antigen recognized by HSA-5 monoclonal antibody

Among the monoclonal antibodies generated against acrosome-reacted human sperm, HSA-5 was shown to react with a sperm antigen localized predominantly to the equatorial region of the acrosome of human sperm and to the head and tail of mouse sperm. This antibody reacted with the methanol-fixed sperm, but not with fresh live sperm. When purified by immunoaffinity column, a major protein band with a molecular mass of approximately 100 kDa on SDS gel was isolated from fresh human sperm extract. The immunospecificity of isolated human sperm protein to this monoclonal antibody was verified by enzyme-linked immunosorbent assay and Western blot analysis. This antigen, designated as HSA-5, was susceptible to proteolytic degradation and revealed multiple immunoreactive bands in Western blot analyses of some preparations. Mouse sperm homogenates showed a similar polymorphic pattern to that of human samples. The tissue specificity of this antigen was examined immunohistochemically using various mouse and human tissues. HSA-5 did not cross-react with any other tissues except for sperm in adult testes and epididymis. This antibody also showed no binding activity to testicular tissue sections from mice of 13 and 21 days of age. The results of our study suggest that the sperm antigen recognized by HSA-5 monoclonal antibody is a differentiation antigen, which is expressed postmeiotically in testicular sperm but not in any somatic tissues.