References 1 Hoffmann, G.W. (1988)in The Semiotics of Cellular Communication in the Immune System (Sercarz E. et al.,

leidoscope

eds), pp. 257-2"1, Springer Vcrlag, New York 2 Hoffmann, (;.W., Kion, T.A. and Grant, M.D. ( I c~91 ) Proc. Natl Acad.

Sci. USA 88, 3060-3064 3 Habeshaw, J., Hounsell, E. and Dalgleish, A. (1992) lmmunol. Today 6, 207-210

Possible roles of anti- Mycobacterium leprae

antibodies in suppression of the cell-mediated

immune response against M. leprae

Leprosy is caused by Mycobac- terium leprae, and is characterized by a broad spectrum of clinical forms, ranging from tuberculoid leprosy on the one pole to lepro- matous leprosy on the other one. Cel l-mediated immuni ty (CMI) plays an important role in protec- tion against M. leprae infection, and tuberculoid-type patients exhibit strong CMI. In contrast , lepro- matous-type patients have absent or reduced cellular immunity. The fac- tors that influence the level of CMI responses are not, as yet, clear ~.2.

Exposure to M. leprae induces CMI and production of anti-M. leprae antibodies, but an inverse correlation between CMI and M. leprae antibody levels develops 3'4. It is possible that the CMI downregu-

lates, by diminishing the M. leprae load, the level of anti-M, leprae antibodies. Here, we propose that anti-M, leprae antibodies down- regulate the CMI.

There have been several reports 5-7 of M. leprae T-cell anti- gens reacting with anti-M, leprae antibodies. Thus, these M. leprae antigens (especially those capable of inducing a protective response) stimulate both a cell-mediated and a humoral response. If the anti- bodies mask the M. leprae antigens expressed on the membranes of antigen-presenting cells, interaction between protective M. leprae anti- gens and T cells will be inhibited.

The production of neutralizing anti-M, leprae antibodies may be influenced by intrinsic factors of the host, environmental factors and the strain of M. leprae; these factors may contribute to the spec- trum of clinical forms. The higher the titre of such anti-M, leprae anti- bodies, the greater the suppression of CM1 and the more likely the development of lepromatous type of leprosy. On the other hand, if

the anti-M, leprae antibody concen- tration is low, then CMI may be strong and the individual might be resistant to M. leprae infection or might develop a tuberculoid type of leprosy.

Om Parkash U. Sengupta

Dept of Immunology, Central JALMA Institute

for Leprosy, Tal Ganj, Agra 282001, India.

References 1 Kaplan, G. and Cohn~ Z.A. (1991) Curr. Opin. lmmunol. 3, 91-96 2 Dharmendra and Chatterjee, K.R. (1955) Lep. Ind. 27, 149-1,54 3 Ridley, D.S. and Jopling, W.H. (1966) Int. J. Lep. 34, 255-273 4 Kaplan, G. and Cohn, Z.A. (1986) lnt. Rev. Exp. Pathol. 28, 45-78 5 Lamb, J.R. and Rees, A.D.M. (1988) Brit. Med. Bull. 44, 600-610 6 Harris, D.P., Backstrom, B.T., Booth, R.J. et al. (1989) J. lmmunol. 143, 2006-2012 7 Watson, J.D. (1989) lmmunol. Today 10, 218-221

Cytokines - A Practical Approach

edited by F.R. Balkwill, 1992. IRL, Oxford University Press, 1991. £25.00 (380 pages) ISBN 019 963214 6

Cytokines are impor tan t in the growth, development and matu- ration of cells, and are central to tissue remodelling and the regu- lation of immune and inflamma- tory responses. Since cytokine bi- ology is of such fundamental import- ance and since the field is advanc- ing rapidly, it is no surprise to find

several new books on the subject in recent years. It is, however, some- thing of a mystery to me why the excel lent 'Pract ical Approach ' series often strays from basing books on groups of techniques (as in 'Gel Electrophoresis of Proteins') into discussing subject areas. Perhaps I would have appreciated this book more had it been entitled 'Cytokine Bioassays - A Practical Approach', since I would not then have been so disappointed by the balance of molecular biology to cell biology techniques. The book does contain an alarming array of bio- assays and, although some chapters are excellent, I feel that newcomers

to the field would benefit from stronger warnings of the dangers of endotoxin contamination and stimu- lation of cells by in vitro handling.

The four chapters (out of 23) which are devoted to molecular analysis of cytokine genes are of mixed qua l i ty with some very demanding techniques described in quite a cursory manner while, in another chapter, two entire pages are devoted to pouring and run- ning agarose gels. A more cohesive policy would have been helpful here. The chapter on quantitative RT-PCR is remarkable in that it completely fails to describe the quantitation of RT-PCR. Although

Immunology Today 5 13 vol 13 No. 12 ? 992