RATIONALE: Interleukin-2 may stimulate a person's white blood cells to kill solid tumor cells. Monoclonal antibodies can locate tumor cells and either kill them or deliver tumor-killing substances to them without harming normal cells.

PURPOSE: Pilot study to examine the effectiveness of interleukin-2 plus monoclonal antibody in treating patients who have solid tumors.

OBJECTIVES: I. Determine the toxic effects of humanized anti-HER2 monoclonal antibodies when administered in combination with interleukin-2 (IL-2) in patients with solid tumors. II. Measure in vitro cytotoxicity using peripheral blood mononuclear cells, plasma, and target cell lines that express HER2 in this patient population. III. Phenotypically characterize effector cells at the time of antibody administration and 24 hours after three days of intermediate dose IL-2 pulsing in these patients. IV. Measure antitumor response in these patients.

OUTLINE: Cohorts of 6 patients are enrolled at 4 antibody dose levels. After at least 6 patients have been treated on study for at least 30 days, the next dose level may be initiated provided that fewer than 2 of the first 6 evaluable patients experience dose limiting toxicity (DLT) related to either the antibody or the combination of antibody with interleukin-2 (IL-2). If 2 or more patients experience DLT, the next cohort is enrolled at the antibody dose midway between the current and previous dose levels. An additional 6 patients are entered at the maximum tolerated dose. On course 1, patients receive IL-2 subcutaneously (SQ) daily on days 1-7 and humanized anti-HER-2 monoclonal antibodies IV over 90 minutes on day 7. Patients receive intermediate dose pulsed IL-2 SQ on days 8-10 and low dose IL-2 SQ on days 11-20. On course 2 and all subsequent courses, patients receive humanized anti-HER2 monoclonal antibodies IV immediately prior to IL-2 (SQ) on day 1 and intermediate dose pulsed IL-2 (SQ) on days 1-3. Patients receive low dose IL-2 (SQ) on days 4-14. Treatment may be delayed up to 7 days to allow for recovery and for tumor restaging, but daily low dose IL-2 is continued in this interval. Patients are followed at 4 weeks and then every 8 weeks until progression or death.

PROJECTED ACCRUAL: Approximately 30 patients will be accrued for this study.

DISEASE CHARACTERISTICS: Histologically confirmed nonhematologic malignancy Refractory disease or disease for which no effective standard therapy exists HER2 overexpression in tumor tissue Measurable or evaluable disease No CNS metastases Hormone receptor status: Not specified

PATIENT CHARACTERISTICS: Age: 18 and over Menopausal status: Not specified Performance status: CALGB 0-1 Life expectancy: At least 3 months Hematopoietic: Absolute granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 times normal SGOT no greater than 5 times normal Alkaline phosphatase no greater than 5 times normal Renal: BUN no greater than 1.5 times normal Creatinine no greater than 1.5 times normal Cardiovascular: No uncontrolled or severe cardiac disease LVEF at least 45% by MUGA or echocardiogram Other: HIV negative No immunologic disease (e.g., autoimmune disease) Negative viral hepatitis antibodies No psychiatric conditions which would prevent compliance with treatment Not pregnant or nursing Fertile patients must use effective contraception No active uncontrolled bacterial, viral, or fungal infection Prior or concurrent malignancy allowed

PRIOR CONCURRENT THERAPY: Biologic therapy: Prior interleukin-2 (IL-2) and/or herceptin allowed No concurrent immunosuppressive drugs or other immunomodulators (other than IL-2) Chemotherapy: At least 6 weeks since nitrosoureas, melphalan, or mitomycin More than 4 weeks since other chemotherapy Endocrine therapy: No concurrent corticosteroids Radiotherapy: More than 4 weeks since prior radiotherapy Surgery: At least 4 weeks since major surgery