IMMUNOLOGICAL SUPPRESSION OF PARASITE REJECTION BY REMOVAL OF SELECTED LYMPHOCYTE POPULATIONS: THE EFFECT OF NEONATAL THYMECTOMY AND ANTI‐THYMOCYTE SERUM ADMINISTRATION ON THE RESISTANCE OF RATS TO INFECTION WITH THE NEMATODE, NIPPOSTRONGYLUS BRASILIENSIS

Abstract

Summary. Neonatally thymectomised rats, infected with IV. brasiliensis, showed significant increases in worm-egg production and parasite survival when compared with sham-thymectomised controls, particularly during the later stages of infection. Treatment of infected rats with rabbit anti-rat thymocyte serum resulted in a highly significant suppression of parasite rejection. The production of reagin-like antibody, directed at antigens of N. brasiliensis, was substantially inhibited in both neonatally thymectomised and anti-rat thymocyte serum treated rats.Neonatal thymectomy combined witb anti-rat thymocyte scrum treatment, produced a much greater loss of resistance (as judged by worm-egg production and parasite survival) than either neonatal thymectomy or anti-rat thymocyte serum alone. Furthermore, reagin-like antibody production was not detected at any stage during primary infection in neonatally thymectomised, anti-rat thymocyte scrum treated rats.It is suggested that the lymphocytes involved in the lymphocyte-mediated component of resistance of rats to N. brasiliensis infection are (a) long-lived and (b) derived from and continually produced by the thymus, or are produced elsewhere and the presence of the thymus is essential for their functional development.INTRODUCTION.

Intestinal Mast Cell and Eosinophil Numbers During Worm Expulsion in Nulliparous and Lactating Rats Infected with <i>Nippostrongylus brasiliensis</i>

“…[1968], M iller [1971] and Murray et al [1971], which postulates that the mast cell amine system was necessary for the release of anti-worm antibodies. The present results also show that the antibodymediated first step in worm rejection functions in lactating rats, and support the conclusion that the immunological deficiency responsible for the failure of worm expulsion in lactating rats is due to a defect in the second step of worm expulsion, which is lymphocyte-dependent [D ineen and Kelly, 1972].…”

“…More recent data have shown that antibodies alone cannot cause worm expulsion but only damages the worms and makes them susceptible to the lymphocyte-dependent expulsive step [Jones and O gilvie, 1971;Keller and K eist, 1972;Kelly and D ineen, 1972a, b;Kelly, 1972]. The present results show that damage to the worms which is known to be antibody-mediated [Jones and O gilvie, 1971] has occurred by day 13 when no observable mast cells are present in the in testine in both nulliparous and lactating rats.…”

Untersuchungen über die Immunelimination von Trichinella spiralis bei Ratten

“…Ansiedlung im Darm und anfangliche Eiausscheidung verliefen bei Infektionen mit N . brasiliensis in neonatal thymektomierten Ratten ungestort, doch verzogerte sich die Wurmelimination bei gleichzeitig verlangerter Eiausscheidung (OGILVIE u. JONES, 1967; KELLY, 1972) bzw. erniedrigten PCA-Titern (WILSON et al, 1967;OGILVIE u. JONES, 1967).…”

“…spiralis in Ratten (GORE et al, 1970 und Mausen (KOZAR et al, 1971; DINETTA MACHNICKA, 1972;LARSH et al, 1972;KOZAR, 1973), mit N . brasiliensis in Mausen (KASSAI et al, 1968) und Ratten (KELLY, 1972) und mit Hymenolepis citelli in Peromyscus maniculatus (WASSOM et al, 1974). Dagegen blieb die Wurmburde bei einmaliger Infektion wie bei Zweitinfektion von Ratten mit Schistosoma mansoni unbeeinfluflt, wahrend alle Untersuchungen uber die Immunelimination von Trichinella spiralis bei Ratten 3 gemessenen Antikorper vermindert waren (MADDISON et al, 1970).…”

Thymectomy in the neonatal rat

“…Mortality from these sources is variable, but several reports exemplify the extent of losses that can be encountered in the rat, such as 10% attributable to surgical procedure, 40% to cannibalism, 25% to 'runting' (Jankovic, Waksman & Amason, 1962;Pinnas & Fitch, ] 966; Kelly, 1972). As well as describing in detail the technique for removal of the thymus in the newborn rat, the present paper places emphasis on certain innovations aimed at minimising this wastage.…”