DISEASE CHARACTERISTICS:

• Histologically confirmed follicular non-Hodgkin's lymphoma (NHL)

  • Relapsed after or refractory to primary therapy
• Progressive disease after at least 1 prior standard therapy, including chemotherapy, radiotherapy, biologic therapy, or bone marrow or stem cell transplantation

• Bidimensionally measurable disease

  • At least one lesion at least 2.0 cm
• No disease refractory to prior rituximab
• No pleural or peritoneal effusion with positive cytology for lymphoma
• No prior aggressive NHL or mantle cell lymphoma
• No chronic lymphocytic leukemia
• No CNS lymphoma

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• WHO 0-2

Life expectancy

• At least 3 months

Hematopoietic

• Hemoglobin at least 8.0 g/dL
• Absolute neutrophil count at least 1,500/mm^3
• Platelet count at least 75,000/mm^3

Hepatic

• Bilirubin no greater than 2.0 mg/dL
• AST and/or ALT no greater than 2 times upper limit of normal

Renal

• Creatinine no greater than 2.0 mg/dL
• No hydronephrosis

Cardiovascular

• No congestive heart failure
• No New York Heart Association class III or IV heart disease
• No myocardial infarction within the past 6 months

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 12 months after study participation
• HIV negative
• No other primary malignancy requiring active treatment (except hormonal therapy)
• No active uncontrolled bacterial, viral, or fungal infection
• No other medical condition that would preclude study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• See Disease Characteristics
• More than 3 weeks since prior biologic therapy for cancer
• More than 6 months since prior antibody therapy for lymphoma
• More than 6 months since prior bone marrow or stem cell transplantation
• No prior IDEC-114 or other anti-CD80 antibody

Chemotherapy

• See Disease Characteristics
• More than 3 weeks since prior chemotherapy for cancer (6 weeks for nitrosoureas or mitomycin)

Endocrine therapy

• More than 3 weeks since prior prednisone

Radiotherapy

• See Disease Characteristics
• More than 3 weeks since prior radiotherapy for cancer
• More than 6 months since prior radioimmunotherapy for lymphoma

Surgery

• More than 4 weeks since prior major surgery (except diagnostic surgery)

Other

• Recovered from prior therapy
• More than 3 weeks since other prior immunosuppressive therapy
• Prior investigational drugs allowed