Summary. Immunostimulation with agents such as BCG or K L H may represent an adjuvant therapy in treating patients with bladder cancer. To investigate the effects of direct instillation and injection of K L H into the bladder of sensitized and nonsensitized rats, K L H was injected Olsson et al. (1973) were able to show statistically significant immunologic reduction in the bladder cancer recurrence rate by immunizing patients with 5 mg K L H (keyhole limpet hemocyanin) intracutaneously. Attempts have also been made to enhance patients' immunreactivity by injecting B C G intralesionally after previous subcutaneous sensitation. In a toxicity study, we tried to obtain information about the histological reactions of K L H injected into the rat bladder, using the same experimental model as Bloomberg et al. (1975), who injected B C G into the dog bladder.
Material and MethodsSixty postpuberal male and female syngenic Wistar rats weighing 168-245 g were divided into two treatment groups: Group I consisted of 30 rats which received no KLH stimulation before KLH injection into the bladder. Group II consisted of 30 rats which were sensitized with two injections of KLH to provoke lymphocyte reacReprint requests should be addressed to: K. F. Klippel tivity. Each rat of Group II received two injections of 0.1 mg KLH s.c. (Calbiochem. 374805, A grade) one week apart, stabilized prior to injection by phosphate buffered saline 0.005 M pH 8.5 in order to obtain the dissociated state (pH 8.6) with fractions of a molecular weight of about 1 million (S 18).Groups I and II were further subdivided into three identical treatment groups of 10 animals each:Sub-groups Ia, IIa: Submucosal injection of sterile normal saline by direct bladder exposure (0.3 ml).Sub-groups Ib, IIb: KLH-instillation 0.5 ml (= 12.5 mg) into the bladder via a polyethylene catheter O 1 ram, left in place for 10 min during anesthesia.Sub-groups Ic, IIc: Submucosal KLH-injection 0.2 ml (= 5 mg) by direct bladder exposure.Anesthesia was induced by ether and continued by Nembutal® 0.2 mg/kg. Three weeks after treatment, the animals were sacrificed and the bladders surgically removed.
ResultsThere was no animal mortality. Intradermal injection of K L H was well-tolerated and showed a mild inflammatory reaction at the skin site in only seven rats. Histological studies on the bladders of the saline-injected animals (Groups Ia and IIa) showed mild vascular congestion and fibrosis consistent with the operative procedure. Nonsensitized rats (Ib) with K L H instillation showed no marked reaction, whereas bladders of the sensitized rats (IIb) showed a slight vascular reaction.The ten nonsensitized rats which received direct injections of K L H (Group Ib) showed mild vascular congestion histologically and activation of flbrocytes with loosely structured nuclei. The mononuclear cell infiltration was equally present in all animals of this group.The animals in Group IIc, pre-sensitized with K L H injections, showed a marked inflammatory reaction with leucocyte infiltration, acti...