PROGRESS IN PROTOZOOLOGY

2.32 I. CUNNINGHAM
RPMI 1640 with 20% foetal bovine serum for the growth of monomorphic
forms of T. brucei. A similar technique of growing bloodstream
forms in co-cultivation with mammalian cells had been attempted 10
years earlier by Le Page (1967) but gave limited results. Hirumi
et al.'s success, however, stimulated further efforts which resulted in
the establishment of similar cultures of other T. brucei stocks (Hill et
al. 1978, B r u n et al. 1979, JenniandBrun 1981).
The following results were obtained by B r u n and his collaborators
in Basel. Several cell lines and primary cell cultures grown in
Eagles MEM supplemented with sera from various animal sources were
tested for their ability to maintain the growth of pleomorphic stocks
of T. b. brucei, T. b. rhodesiense, and T. b. gambiense. The mountain
vole (Microtus montanus) embryo fibroblast-like cells (MEF) and rabbit
embryo fibroblasts grown in medium with rabbit or human sera were
most successful for supporting long term cultivation of blood-stream
forms. The cultures could be initiated with either trypanosomes from
infected mouse blood or from metacyclic forms from infected Glossina.
The "cultivated" bloodstream trypanosomes were (a) pleomorphic, (b)
infective to mice, and (c) transformed into procyclic forms when added
to medium SDM-79 (B r u n and Schonenberger 1979) and incubated
at 28°C. Of interest was the finding that tsetse fly metacyclic forms
transformed rapidly into bloodstream forms in the in vitro systems,
but without the expression of new variable antigenic types (VATs) during
the first 50 h in culture. During this period metacyclic antigens
had increased 10-20 fold. At 50 h the trypanosomes were collected,
irradiated, and used to imunize mice. These mice were completely protected
from infection by tsetse flies' bites containing the homologous
T. brucei stock.
(2) Trypanosoma congolense
Media used by the early workers for the cultivation of T. congolense
were variations of a liquid medium prepared by combining R i ng
e r's solution with citrated blood (for references, see Tobie 1958).
These media and the diphasic blood agar medium of Tobie (1958) were
suitable for growing procyclic noninfective trypanosomes transformed
from bloodstream forms from mammalian hosts. Trager (1959) observed
the growth of procyclic forms in Glossina organ cultures using
a liquid medium enriched with tsetse pupal extract. The liquid medium
of Cunningham (1977) was suitable for the cultivation of procyclics,
which had been transformed from bloodstream forms in the medium
containing tsetse fly alimentary tract tissues. The culture system of
Steiger et al. (1977) consisting of a feeder layer of tsetse fly cells
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