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Adoptive transfer of protection to Taenia taeniaeformis infection in rats with immune spleen cells
Inrernokmal
Journalfor Parasitology,
Vol. 24. No. 3, pp. 413415, 1994 1994 Australian Society for Parasitology El&x Science Lid Printed in Great Britain. All rights reserved CO2&7519/94%7.00+ 0.00
Copyright 0
Pergamon
0020-7519(94)E0009-C
RESEARCH
NOTE
ADOPTIVE
TRANSFER OF PROTECTION TO TAEiVIA INFECTION IN RATS WITH IMMUNE SPLEEN CELLS
TAENIAEFORA4IS
KAZUHITO
Asmo,*t
AKIRA ITO,$ KAZUHITO IKEDA~
and KEN-ICHI OKAMOTO~
tDepartment of MedicalBiology, School of Medicine, Showa University, l-5-8 Hatanodai, Shinagawa-ku, Tokyo 142 SDepartment of Parasitology, Gifu University School of Medicine, Gifu 500, Japan (Received 4 November 1993; accepted 11 January 1994)
Abstract-ASANO K., IT’OA., IKEDA K. and OKAMOTOK. 1994. Adoptive transfer of protection to Taenia raeniaeformis infection in rats with immune spleen ceils. International Journalfor Parasitology 241413415. The effector mechanism of the protection against re-infection with eggs of Taenia taeniaeformis was evaluated in rats by analysing protection dynamics against an ongoing primary infection. Immune spleen cells were prepared from F344 donor rats 10 days after oral inoculation with 200 eggs and used for adoptive transfer experiments. When F344 recipient rats were injected intravenously with immune spleen cells (2 x lOa) from 2 to 48 h after a primary egg inoculation, there was a statistically significant reduction in the number of metacestodes recovered at day 30 of the infection. The highest protection figures were obtained in rats given immune cells at 12 or 24 h of the primary infection. The maximum reduction induced with immune cells was 92% when they were injected at 12 h of the ongoing infection. It is strongly suggested that the vulnerable stage of the parasite damaged by immune spleen cells is the initial stage of infection (oncosphere and post-oncosphere stages in the liver within 2 days, especially between 12 and 24 h). INDEX KEY WORDS: Taenia taeniaeformis; rats; spleen cells; passive transfer; ongoing infection.
THE immune
mechanisms against re-infection with eggs of Taenia taeniaeformis have substantially been analysed for many years (reviewed by Lightowlers, Mitchell & Rickard, 1993). It has been known that immune serum prepared from rats or mice infected with eggs contains the host-protective antibodies and the vulnerable stage of this parasite is the oncosphere and post-oncosphere within several days of egg infection (Musoke & Williams, 1975). In contrast, there are few reports concerning transfer of immunity with immune cells (Kwa & Liew, 1975). Most recently, we have reported that rats adaptively immunized with spleen cells prepared from donors from day 10 onward of the primary egg infection (immune spleen cells) just before egg challenge became highly resistant to the egg challenge and the effector cells were 0X22-helper T cells in the spleen (Asano, Ito & Okamoto, 1993). In the present study, we have done additional experiments in order to get further information on the target
*To whom all correspondence should be addressed.
of the parasite and to stress that immune spleen cells themselves are the effecters even when they are transferred into rats which have just been infected but are not yet expressing acquired immunity. Specific-pathogen free, male rats of an inbred F344 strain, purchased from Nihon SLC Co., Ltd. (Shizuoka Japan), were used for egg inoculations at 5 weeks of age. Conditions for housing rats, preparation of eggs for infection, inoculation with eggs and assay of the protection induced with adoptive transfer were similar to those reported previously (Asano et al., 1993). Immune spleen cells were prepared from rats infected with 200 eggs 10 days before use, whereas normal spleen cells were prepared from age-matched, uninfected rats. All recipients orally inoculated with 200 eggs were injected with 2 x 108spleen cells from 2 h to 6 days after egg infection. The experimental schedules and the results are summarized in Table 1. When recipient rats were injected with immune spleen cells at 2 and 48 h after egg inoculations, they showed some level of protection with approximately 50% reduction in the number of 413
K. ASANO et al.
414
TABLE I-PASSIVEPROTECTION IN RATSINOCULATED WITH EGGSOF Tuerzia taeni~eform~ AND FOLLOWEDBY INJECTION OF IMMUNE
Hours or days of cell injection? Experiment 1 2h 12 h 24h(lday) Experiment 2 2h 48 h (2 days) 72 h (3 days) 6 days
SPLEEN
CELLS*
Type of cells injected (2 X Ion/O.5 ml)
No. of rats infected
No. of metacestodes (Mean +ZS.D.)
Immune Normal Immune Normal Immune Normal
515 NT 616 616 515 NT
63.6 f 6.8@ NT 10.5 i 3.51b 130.7 f 24.9 16.8 i 6.22d NT
Immune Normal Immune Normal Immune Normal Immune Normal
515 414 515 NT 5j5 313 515 NT
61.2 * 144.8 f 60.0 f NT 127.4 f 137.0 f 130.6 f NT
120 15.5’ 8.468 18.9h 27.9 25.1~
*Immune spleen cells were prepared from F344 male rats each orally inoculated with 200 eggs of Taeniu taeniaeformis 10 days prior to cell collection, whereas normal spleen cells were prepared from uninfected age-matched rats. ?A11recipient F344 rats of 5 weeks of age inoculated orally with 200 eggs (Oh)were injected intravenously with 2 x lo* cells at different timings from 2 h to 6 days of the ongoing infection and killed 30 days later to count the number of metacestodes developed in the liver. a vs b or d, a, b or d vs e, e or g vs f, h, i or j, P < 0.01 (Mann-Whitney U test), b vs d, e vs g: P > 0.05 (not significant). NT, not tested.
metacestodes in the liver when they were killed 30 days after egg inoculation (P < 0.01, MannWhitney U test). The highest figures of 92 and 90% reductions were obtained in recipients injected with immune spleen cells at 12 and 24 h after egg inoculation, respectively. There was no effect of immune cells when they were injected at 72 h after egg inoculation (Table 1). The protection figures in recipients injected with immune cells 2 h after egg inoculation were weaker than those given at 12 and 24 h. At present, it is difficult for us to explain the biological reasons for the lower effect of immune cells injected 2 h after egg inoculation, since those cells injected 1 h before egg inoculation (Asano et al., 1993) showed a similar effect induced at 12 or 24 h after infection reported in this paper. Thus, it remains to be determined whether the oncosphere in the intestinal lumen, intestinal tissue or liver is the target for attack by immune spleen cells. Musoke & Williams (1975) and Heath & Pavloff (1975) reported using serum transfer experiments that the vulnerable stage to immune serum was the oncosphere which could survive at least during the first 24 h in the liver, since oncospheres can reach the liver tissue within a few hours of egg inoculation (Musoke & Williams 1975; Bergh, Lightowlers, Sullivan, Mitchell & Rickard, 1990). The present established
results revealed that adoptively transferred immune spleen cells had a protective effect in recipient rats even when they were transferred 24 h after egg inoculation. Thus, it seems probable to speculate that the main target in this experimental system, at least, is the oncosphere in the liver. This is the first demonstration of the protective effect of the immune cells transferred into naive rats which have just been infected with the parasite but not yet expressing acquired immunity. It is interesting to know whether or not immune cells for adoptive transfer experiments, prepared from donors at not 10 but 20 or 30 days of egg inoculation, would be capable of transferring protection against later stages of the ongoing infection in recipients.
REFERENCES ASANO K., ITO A. & OKAMOTO K. 1993.The role of
0X22-helper T cells in protective immunity to reinfection with Taenia taeniueformis in rats. Parasite Immunology 1% 663-668. Bc?GHH.O., LIGHTOWLERSM.W.,S~LLIVAND.,MIT~HELL G. F.& RICKARDM. D. 1990. Stage-specific immunity to Taenia taeniaeformis infection in mice: a histological study of the infection in mice vaccinated with either oncosphere or metacestode antigens. Parasite Immunology 12: 153162.
Research Note HEATH D. D. & PAVLOFFP. 1975. The fate of Tuenia taeniueformis oncospheres in normal and passively protected rats. International Journalfor Parasitology 5: 83-88. KWA B. H. & LIEW F. Y. 1975. The role of cell-mediated immunity in Taenia taeniaeformis infections. Southeast Asian Journal of Tropical Medicine and Public Health 6: 483487.
415
LIGHTOWLERS M. W., MITCHELLG. F. & RICKARDM.D. 1993. Cestodes. In: Immunology and Molecular Biology of Parasitic Infections (Edited by WARRENK. S.), pp. 43% 472. Blackwell Scientific Publications, Oxford. MUSOKEA. J. & WILLIAMSJ. F. 1975. The immunological response of the rat to infection with Taeniu taeniaeformis. Immunology 29: 855-866.
Journalfor Parasitology,
Vol. 24. No. 3, pp. 413415, 1994 1994 Australian Society for Parasitology El&x Science Lid Printed in Great Britain. All rights reserved CO2&7519/94%7.00+ 0.00
Copyright 0
Pergamon
0020-7519(94)E0009-C
RESEARCH
NOTE
ADOPTIVE
TRANSFER OF PROTECTION TO TAEiVIA INFECTION IN RATS WITH IMMUNE SPLEEN CELLS
TAENIAEFORA4IS
KAZUHITO
Asmo,*t
AKIRA ITO,$ KAZUHITO IKEDA~
and KEN-ICHI OKAMOTO~
tDepartment of MedicalBiology, School of Medicine, Showa University, l-5-8 Hatanodai, Shinagawa-ku, Tokyo 142 SDepartment of Parasitology, Gifu University School of Medicine, Gifu 500, Japan (Received 4 November 1993; accepted 11 January 1994)
Abstract-ASANO K., IT’OA., IKEDA K. and OKAMOTOK. 1994. Adoptive transfer of protection to Taenia raeniaeformis infection in rats with immune spleen ceils. International Journalfor Parasitology 241413415. The effector mechanism of the protection against re-infection with eggs of Taenia taeniaeformis was evaluated in rats by analysing protection dynamics against an ongoing primary infection. Immune spleen cells were prepared from F344 donor rats 10 days after oral inoculation with 200 eggs and used for adoptive transfer experiments. When F344 recipient rats were injected intravenously with immune spleen cells (2 x lOa) from 2 to 48 h after a primary egg inoculation, there was a statistically significant reduction in the number of metacestodes recovered at day 30 of the infection. The highest protection figures were obtained in rats given immune cells at 12 or 24 h of the primary infection. The maximum reduction induced with immune cells was 92% when they were injected at 12 h of the ongoing infection. It is strongly suggested that the vulnerable stage of the parasite damaged by immune spleen cells is the initial stage of infection (oncosphere and post-oncosphere stages in the liver within 2 days, especially between 12 and 24 h). INDEX KEY WORDS: Taenia taeniaeformis; rats; spleen cells; passive transfer; ongoing infection.
THE immune
mechanisms against re-infection with eggs of Taenia taeniaeformis have substantially been analysed for many years (reviewed by Lightowlers, Mitchell & Rickard, 1993). It has been known that immune serum prepared from rats or mice infected with eggs contains the host-protective antibodies and the vulnerable stage of this parasite is the oncosphere and post-oncosphere within several days of egg infection (Musoke & Williams, 1975). In contrast, there are few reports concerning transfer of immunity with immune cells (Kwa & Liew, 1975). Most recently, we have reported that rats adaptively immunized with spleen cells prepared from donors from day 10 onward of the primary egg infection (immune spleen cells) just before egg challenge became highly resistant to the egg challenge and the effector cells were 0X22-helper T cells in the spleen (Asano, Ito & Okamoto, 1993). In the present study, we have done additional experiments in order to get further information on the target
*To whom all correspondence should be addressed.
of the parasite and to stress that immune spleen cells themselves are the effecters even when they are transferred into rats which have just been infected but are not yet expressing acquired immunity. Specific-pathogen free, male rats of an inbred F344 strain, purchased from Nihon SLC Co., Ltd. (Shizuoka Japan), were used for egg inoculations at 5 weeks of age. Conditions for housing rats, preparation of eggs for infection, inoculation with eggs and assay of the protection induced with adoptive transfer were similar to those reported previously (Asano et al., 1993). Immune spleen cells were prepared from rats infected with 200 eggs 10 days before use, whereas normal spleen cells were prepared from age-matched, uninfected rats. All recipients orally inoculated with 200 eggs were injected with 2 x 108spleen cells from 2 h to 6 days after egg infection. The experimental schedules and the results are summarized in Table 1. When recipient rats were injected with immune spleen cells at 2 and 48 h after egg inoculations, they showed some level of protection with approximately 50% reduction in the number of 413
K. ASANO et al.
414
TABLE I-PASSIVEPROTECTION IN RATSINOCULATED WITH EGGSOF Tuerzia taeni~eform~ AND FOLLOWEDBY INJECTION OF IMMUNE
Hours or days of cell injection? Experiment 1 2h 12 h 24h(lday) Experiment 2 2h 48 h (2 days) 72 h (3 days) 6 days
SPLEEN
CELLS*
Type of cells injected (2 X Ion/O.5 ml)
No. of rats infected
No. of metacestodes (Mean +ZS.D.)
Immune Normal Immune Normal Immune Normal
515 NT 616 616 515 NT
63.6 f 6.8@ NT 10.5 i 3.51b 130.7 f 24.9 16.8 i 6.22d NT
Immune Normal Immune Normal Immune Normal Immune Normal
515 414 515 NT 5j5 313 515 NT
61.2 * 144.8 f 60.0 f NT 127.4 f 137.0 f 130.6 f NT
120 15.5’ 8.468 18.9h 27.9 25.1~
*Immune spleen cells were prepared from F344 male rats each orally inoculated with 200 eggs of Taeniu taeniaeformis 10 days prior to cell collection, whereas normal spleen cells were prepared from uninfected age-matched rats. ?A11recipient F344 rats of 5 weeks of age inoculated orally with 200 eggs (Oh)were injected intravenously with 2 x lo* cells at different timings from 2 h to 6 days of the ongoing infection and killed 30 days later to count the number of metacestodes developed in the liver. a vs b or d, a, b or d vs e, e or g vs f, h, i or j, P < 0.01 (Mann-Whitney U test), b vs d, e vs g: P > 0.05 (not significant). NT, not tested.
metacestodes in the liver when they were killed 30 days after egg inoculation (P < 0.01, MannWhitney U test). The highest figures of 92 and 90% reductions were obtained in recipients injected with immune spleen cells at 12 and 24 h after egg inoculation, respectively. There was no effect of immune cells when they were injected at 72 h after egg inoculation (Table 1). The protection figures in recipients injected with immune cells 2 h after egg inoculation were weaker than those given at 12 and 24 h. At present, it is difficult for us to explain the biological reasons for the lower effect of immune cells injected 2 h after egg inoculation, since those cells injected 1 h before egg inoculation (Asano et al., 1993) showed a similar effect induced at 12 or 24 h after infection reported in this paper. Thus, it remains to be determined whether the oncosphere in the intestinal lumen, intestinal tissue or liver is the target for attack by immune spleen cells. Musoke & Williams (1975) and Heath & Pavloff (1975) reported using serum transfer experiments that the vulnerable stage to immune serum was the oncosphere which could survive at least during the first 24 h in the liver, since oncospheres can reach the liver tissue within a few hours of egg inoculation (Musoke & Williams 1975; Bergh, Lightowlers, Sullivan, Mitchell & Rickard, 1990). The present established
results revealed that adoptively transferred immune spleen cells had a protective effect in recipient rats even when they were transferred 24 h after egg inoculation. Thus, it seems probable to speculate that the main target in this experimental system, at least, is the oncosphere in the liver. This is the first demonstration of the protective effect of the immune cells transferred into naive rats which have just been infected with the parasite but not yet expressing acquired immunity. It is interesting to know whether or not immune cells for adoptive transfer experiments, prepared from donors at not 10 but 20 or 30 days of egg inoculation, would be capable of transferring protection against later stages of the ongoing infection in recipients.
REFERENCES ASANO K., ITO A. & OKAMOTO K. 1993.The role of
0X22-helper T cells in protective immunity to reinfection with Taenia taeniueformis in rats. Parasite Immunology 1% 663-668. Bc?GHH.O., LIGHTOWLERSM.W.,S~LLIVAND.,MIT~HELL G. F.& RICKARDM. D. 1990. Stage-specific immunity to Taenia taeniaeformis infection in mice: a histological study of the infection in mice vaccinated with either oncosphere or metacestode antigens. Parasite Immunology 12: 153162.
Research Note HEATH D. D. & PAVLOFFP. 1975. The fate of Tuenia taeniueformis oncospheres in normal and passively protected rats. International Journalfor Parasitology 5: 83-88. KWA B. H. & LIEW F. Y. 1975. The role of cell-mediated immunity in Taenia taeniaeformis infections. Southeast Asian Journal of Tropical Medicine and Public Health 6: 483487.
415
LIGHTOWLERS M. W., MITCHELLG. F. & RICKARDM.D. 1993. Cestodes. In: Immunology and Molecular Biology of Parasitic Infections (Edited by WARRENK. S.), pp. 43% 472. Blackwell Scientific Publications, Oxford. MUSOKEA. J. & WILLIAMSJ. F. 1975. The immunological response of the rat to infection with Taeniu taeniaeformis. Immunology 29: 855-866.