SEMG-1 expression in early stage chronic lymphocytic leukemia.
OBJECTIVE
Chronic lymphocytic leukemia (CLL) is an indolent disease. It is currently recommended that patients with CLL stages 0 and I follow a watchful waiting strategy. These patients are, therefore, a suitable group for testing immunotherapeutic approaches to avoid problems of immunosuppression as a result of disease progression and chemotherapy. In this study, we investigated the expression of SEMG-1 in early CLL to determine the suitability of SEMG-1 as a target for further development of tumor vaccines for early CLL.


METHODS
A combination of reverse transcriptase (RT)-polymerase chain reaction (PCR) and immunocytochemistry was used to evaluate the expression of SEMG-1 in early CLL. The results were correlated with Zap 70 expression. Recombinant SEMG-1 protein was used in an enzyme-linked immunosorbent assay (ELISA) to determine the presence of SEMG-1 antibodies (Ab) in serum from these patients.


RESULTS
The SEMG-1 gene was expressed in 19/41 (46%) patients with early CLL. Gene expression was associated with protein synthesis in CLL cells. Protein expression, however, was heterogeneous within individual patients. Only transcripts encoding the SEMG-1(50) variant and not SEMG-1(43) were detected. SEMG-1(50) was expressed irrespective of the Zap 70 status. High-titer SEMG-1 IgG but not IgM Ab were detected in some of these patients, suggesting that SEMG-1-reactive immune responses are intact within the immune repertoire of early CLL patients.


CONCLUSIONS
SEMG-1 is expressed in nearly half of patients with early CLL and may be a target for further investigations into its use for immunotherapy of early CLL.
Ahmed
Sharif Uddin
SU
Harrington Regional Medical Center Inc., Amarillo, Texas, USA.
Meklat
Farouk
F
Shahriar
Masum
M
Zhang
Jian
J
Mastulov
Suhkrob
S
Giannakouros
Thomas
T
Jewell
Andrew
A
Zhang
Yana
Y
Lim
Seah H
SH
D000917:Antibody Formation; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D019496:Cancer Vaccines; D004797:Enzyme-Linked Immunosorbent Assay; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007150:Immunohistochemistry; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000097:blood / Q000276:immunology* / Q000378:metabolism / Q000517:prevention & control; D009367:Neoplasm Staging; D020133:Reverse Transcriptase Polymerase Chain Reaction; D029607:Seminal Vesicle Secretory Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000235:genetics / Q000276:immunology / Q000378:metabolism
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D019496:Cancer Vaccines; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D029607:Seminal Vesicle Secretory Proteins; C424482:seminal vesicle-specific antigen; D051746:ZAP-70 Protein-Tyrosine Kinase