Inclusion Criteria:

• Metastatic renal clear cell adenocarcinoma, histologically proven by biopsy of the primary tumour and/or a metastasis. If a fresh specimen is obtained for diagnostic purposes, it may be frozen and stained for 5T4. Prior nephrectomy is not required.
• Requiring treatment with IL-2 and able to tolerate a high dose schedule per institutional standards.
• Aged 18 years or more.
• Performance status (ECOG) 0 or 1.
• Expected survival longer than three months.
• No clinically active autoimmune disease.
• Total white cell count greater than or equal to 3 x 109/l.
• Platelet count greater than or equal to 90,000/mm3.
• Serum creatinine 1.6 mg/dl or less.
• Total bilirubin 1.6 mg/dl or less.
• Serum AST/ALT greater than or equal to three times the upper limit of normal or 5 times upper limit of normal if liver metastases are present.
• Able to give written informed consent and to comply with the protocol.
• Women must be either post menopausal, rendered surgically sterile or practising a reliable form of contraception (hormonal, intrauterine device or barrier). Men must practise an effective form of birth control, such as barrier protection.
• Normal cardiac stress test if the patients are older than 50 years of age or have symptoms of cardiac disease.
• Normal pulmonary function tests if the patient is a smoker or is known to have primary lung disease.

Exclusion Criteria:

• Pregnancy, lactation or lack of effective contraception in fertile men and women of childbearing potential.
• Intercurrent serious infections within the 28 days prior to entry to the trial.
• Known to be HIV positive because HIV infection can lead to serious adverse events with vaccination and/or high-dose IL-2.
• Life threatening illness unrelated to cancer.
• Cerebral metastases.
• History of allergic response to previous vaccinia vaccinations.
• Participation in any other clinical trial within the previous 30 days .
• Previous malignancies within the last two years other than successfully treated squamous carcinoma of the skin or in situ carcinoma of the cervix treated with cone biopsy.
• Previous history of major psychiatric disorder requiring hospitalisation or any current psychiatric disorder that would impede the patient's ability to provide informed consent or to comply with the protocol.
• Corticosteroids unless used as an antiemetic.
• Family contact with active eczema, exfoliative skin disorder, pregnancy or other cause of immunocompromise.