A monoclonal antibody (RP-3) that depletes rat neutrophils selectively in vivo was developed by hybridization of mouse myeloma cells (P3-X63.Ag8.653) and spleen cells of BALB/c mice sensitized with peritoneal neutrophils of WKA/Hok rats. RP-3 reacted with rat neutrophils but not with lymphocytes, macrophages, natural killer cells, basophils, eosinophils, or tissues of various organs. The mitogenic responsiveness to concanavalin A (ConA), phytohemagglutinin (PHA), and lipopolysaccharide (LPS) of rats given RP-3 was not significantly different from that of normal rats. Administration of RP-3 into the peritoneal cavity of rats that had been kept under specific pathogen-free (SPF) or clean conditions induced selective depletion of circulating neutrophils to under 100/mm3 (0.5% WBC). The numbers of monocytes, lymphocytes, and platelets were not changed. Administration of 2 ml of RP-3 reduced blood neutrophils to under 100/mm3 for approximately 24 h, and administration of 1 ml caused depletion for approximately 12 h.

We analyzed anti-Cytomegalovirus (CMV) IgG and IgM antibody (EIA) and anti-Epstein-Barr virus (EBV) viral capsid antigen (VCA) IgG and IgM antibody (FA) in adults during 1994-1999. We examined these IgM sero-positive patient's medical records, and diagnosed CMV mononucleosis and EBV mononucleosis. Anti-CMV antibody positive rates decreased from 87.6% in 1994 to 77.8% in 1999. Especially in twenties, anti-CMV antibody positive rates decreased from 65.2% in 1994 to 53.3% in 1999. On the other hand, anti-EBV VCA antibody positive rates were not changed (91-94%). Number of cases of CMV mononucleosis increased from 2 cases in 1994 to 16 cases in 1999, but EBV mononucleosis was not changed. These results suggested that increasing cases of CMV mononucleosis was influenced by decreasing anti-CMV antibody positive rate.

We investigated the role of neutrophils in increased vascular permeability by a selective reduction of neutrophils using a monoclonal antibody, RP-3. An intraperitoneal injection of RP-3 not only selectively depleted peripheral blood neutrophils, but prevented the neutrophil infiltration to the tissues. Proteose peptone, zymosan, and BCG induced three different types of inflammatory edema, showing the early phase only, early plus late phase, and the late phase only, respectively. Only the late phase response of zymosan and BCG was inhibited by a depletion of neutrophils by RP-3, though the early phase response induced by proteose peptone and zymosan was not affected. Reconstitution of neutrophil-depleted rats by in situ injection of these cells restored the inflammatory edema induced by BCG, depending upon the number of neutrophils injected.

[Case report] A 65-year-old male war admitted to a local hospital because of fever. He was treated with piperacillin and clindamycin without noticeable effect. He began to complain of loss of vision on the third hospital day and culture of the blood specimen yielded Klebsiella pneumoniae. He was diagnosed as endophthalmitis and referred to our hospital for further examination. The hematological laboratory test showed leukocytosis (12,700/microliter) and increased CRP (20.4 mg/dl). A computed tomographic (CT) scan of the thorax revealed multiple lung abscesses. An abdominal ultrasonographic scan and a CT scan of the abdomen revealed multiple liver abscesses. We drained the abscess in the liver and Klebsiella pneumoniae was detected from the sample of aspirated fluid and his sputum. Meropenem was administered intravenously. Fever started to improve on the tenth hospital day and the size of both liver and lung abscesses were reduced. He has lost vision of his right eye. He was discharged after sixty days. He did not have any immunosuppressive underlying disease including HIV infection and diabetes mellitus which cause these lesions.

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