Dynamics of oogenesis in the tropical anuranRana tigrina (Amphibia: Ranidae) with special reference to vitellogenic cycles in wild-caught and captive flogs

The ovarian cycle ofRana tigrina was analysed by quantifying the developing oocytes (classified into stages on the basis of diameter) and atretic ones at monthly intervals. Stages I to IV represent oocytes in the first growth phase and the remaining ones the vitellogenic or second growth phase. Stages I–III occurred year round but exhibited significant variation in their number. The number of stage II oocytes always dominated the other stages. Recruitment of oocytes to stages IV and V in April marked the initiation of vitellogenic growth in all specimens. Of the 30 to 35% second growth phase oocytes, 25 to 28% reached ovulatory sizes by June. After spawning the ovarian mass declined drastically from 15 to 0.2% of body mass in July. Atresia was maximal (5%) in August. In other months, it was less than 1.5% of the total oocytes. Oogenic episodes occurred in March and July yielding new oocytes. The number of first growth phase oocytes fluctuated from 65 to 95%. The fluctuation was inversely correlated with the second growth phase oocytes indicating a 30 to 35% annual turnover rate of oocytes in the frog. The final egg number/ovarian mass is positively correlated with the snout-vent length as well as body mass of the frogs.R. tigrina produces about 4000 eggs/100g body mass. Further, the mean number of yolky eggs/100 g body mass and the total volume (V) of eggs/frog were highly correlated. Frogs living in captivity produced fewer eggs compared to the wild ones (3594 ± 227 in captivevs 4704 ± 317 in wild frogs). Also, these frogs failed to breed though they showed amplexus with breeding males. Injection of desoxycorticosterone acetate however induced spawning in 4 out of 5 frogs. They released about 3000 eggs each. Captivity seems to mainly impair breeding and to a little extent the vitellogenic growth of oocytes inR. tigrina.     

Evaluating second year cropping on jhum fallows in Mizoram, north-eastern India: Energy and economic efficiencies

Energy and economic efficiencies were evaluated on young (6 year) and old (20 year) jhum fields in Mizoram, north-eastern India during second year of cropping, and were compared with those in the first year. The effect of auxiliary measures such as tilling the soil or application of fertilizers (chemical or farm-yard manure or both in combination) was also examined on energy and economic efficiencies. The results indicated that traditional jhum cultivation is labour intensive and energy efficient, producing almost 15–20 times of energy invested. Energy and economic efficiencies decline with shortening of jhum cycle. These efficiencies decline further from first to second year of cropping. Tilling is not useful to improve either energy or economic efficiency. Fertilizer application, which is though profitable from the point of view of economic efficiency, is highly energy inefficient. Application of fertilizers during second year cropping can be encouraged. Organic manuring may be a better option than others to alleviate energy efficiency. However, a combination of organic and inorgamic manuring could be the best option to enhance economic efficiency.     

Mechanisms regulating the ovarian cycle in the frog Rana cyanophlyctis: effect of unilateral ovariectomy, season, feeding, human chorionic gonadotrophin, and estradiol-17 beta

Effects of 30-day unilateral ovariectomy (ULO) on compensatory ovarian hypertrophy (COH) was studied in adult frog Rana cyanophlyctis in relation to reproductive phase/season, feeding, and treatment with human chorionic gonadotrophin (HCG) or estradiol-17 beta. Compensatory growth of the remaining ovary was assessed in terms of weight as well as changes in the dynamics of the pool sizes of different oocytes viz., first growth phase (FGP), medium-sized second growth phase (MSGP), large-sized second growth phase (LSGP), and atretic oocytes. The frogs were fed with live guppies 6 days a week. The effect of underfeeding on COH was studied in the frogs fed once a week. The ovaries removed at operation and those of the sham-operated frogs were used for comparison (controls). COH occurred in both pre- and postbreeding phases (February and November, respectively). In both instances follicular atresia was greatly reduced. In February, COH was due to recruitment of both MSGP and LSGP oocytes. The number of these oocytes increased significantly over controls, and the ovarian weight nearly doubled. However, in November COH occurred because of an increase in FGP oocytes and therefore total oocytes, but there were no changes in the ovarian weights. Administration of 20 IU HCG (6 days a week) had no influence on the basic pattern of COH-response exhibited by the remaining ovary in relation to reproductive phase/season, but it increased the recruitment of oocytes, i.e., FGP oocytes in November and SGP oocytes in February. Follicular atresia was drastically reduced with HCG. Underfeeding or treatment with estradiol-17 beta abolished the COH in both February and November.(ABSTRACT TRUNCATED AT 250 WORDS)     

Conformation of the C-terminal pentapeptide—the ‘message sequence’—of tachykinins as determined by consensus dynamic

The tachykinins are a family of gastrointestinal peptides comprising eight members: substance P, neurokinin A, neurokinin B, eledoisin, physalemin, uperolein, kassinin and phyllomedusin. Consensus dynamics was carried out on an ensemble of seven tachykinins to determine the binding conformation of the common C-terminal fragment: Phe-X-Gly-Leu-Met-NH ₂ ,the ’message sequence’ of tachykinins. Three binding modes for the C-terminal pentapeptide were determined. The first binding conformation is folded due to an intramolecular H-bond between the NH of the variable residue (X) and CO of Met. Other features include γ-bends at both the variable amino acid (X) and at Gly. The global minimum of the simulation has this conformation for the C-terminal pentapeptide. The other two binding modes have slightly higher energies. The second is chiefly characterized by a β-turn around the segment X-Gly-Leu-Met, with additional β-bends at the variable amino acid (X) and Met. The final binding conformation is composed of β-bends around the variable amino acid (X) and Leu, and a ’pseudo’ γ-bend at the terminal Met. This paper was presented at the MBU Silver Jubilee Symposium on Structural Biology and 24th Annual Meeting of the Indian Biophysical Society held at Indian Institute of Science, Bangalore, Dec. 9–12, 1996.     

Gonad morphology,oocyte development and spawning cycle of the calanoid copepod <Emphasis Type="Italic">Acartia clausi</Emphasis>

Information on gonad morphology and its relation to basic reproductive parameters such as clutch size and spawning frequency is lacking for Acartia clausi, a dominant calanoid copepod of the North Sea. To fill this gap, females of this species were sampled at Helgoland Roads from mid March to late May 2001. Gonad structure and oogenesis were studied using a combination of histology and whole-body-analysis. In addition, clutch size and spawning frequency were determined in incubation experiments, during which individual females were monitored at short intervals for 8 and 12 h, respectively. The histological analysis revealed that the ovary of A. clausi is w-shaped with two distinct tips pointing posteriorly. It is slightly different from that of other Acartia species and of other copepod taxa. From the ovary, two anterior diverticula extend into the head region, and two posterior diverticula extend to the genital opening in the abdomen. Developing oocytes change in shape and size, and in the appearance of the nucleus and the ooplasm. Based on these morphological characteristics, different oocyte development stages (OS) were identified. Mitotically dividing oogonia and young oocytes (OS 0) were restricted to the ovary, whereas vitellogenic oocytes (OS 1–4) were present in the diverticula. The development stage of the oocytes increased with distance to the ovary in both, anterior and posterior diverticula. Most advanced oocytes were situated ventrally, and their number varied between 1 and 18, at a median of 4. All oocyte development stages co-occur indicating that oogenesis in A. clausi is a continuous process. These morphological features reflect the reproductive traits of this species. In accordance with the low numbers of mature oocytes in the gonads, females usually produced small clutches of one to five eggs. Clutches were released throughout the entire observation period at intervals of 90 min (median) resulting in mean egg production rates of 18–28 eggs female⁻¹ day⁻¹.     

Plant regeneration from protoplasts ofCapsicum annuum L. cv. California Wonder

Plant regeneration from mesophyll protoplasts of pepper,Capsicum annuum L. cv. California Wonder has been demonstrated via shoot organogenesis. Protoplasts isolated from fully expanded leaves of 3-week-old axenic shoots when cultured in TM medium supplemented with 1 mg l ⁻¹ NAA, 1 mg l ⁻¹ 2,4-D, 0 5 mg l ⁻¹ BAP (CM 1) resulted in divisions with a frequency ranging from 20–25 %. Antioxidant ascorbic acid and polyvinylpyrrolidone (PVP) in the medium and incubation in the dark helped overcome browning of protoplasts. Microcalli and macrocalli were formed in TM medium containing 2 mg l ⁻¹ NAA and 0.5 mg l ⁻¹ BAP (CM II) and MS gelled medium containing 2 mg 1 ⁻¹ NAA and 0 5 mg 1 ⁻¹ BAP (CM III), respectively. Regeneration of plantlets was possible via caulogenesis. Microshoots, 2–5 percallus appeared on MS gelled medium enriched with 0.5 mg l ⁻¹ IAA, 2mg l ⁻¹ GA and l0mg l ⁻¹ BAP (CM IVc). Rooting of microshoots was obtained on half strength gelled medium containing 1 mg l ⁻¹ NAA and 0.5mg l ⁻¹ BAP. Protoplasts isolated from cotyledons failed to divide and degenerated eventually.     

Flowcytometric assessment of intracellular interferon -γ production in human CD4 + ve T-cells on mycobacterial antigen stimulation

Interferon-(IFN-γ) has been considered to be a critical protective immunomodulatory component against Mycobacterium tuberculosis (M. tb.) infection. In this study T-cell proliferation and IFN-γ production upon stimulation with M. tb. were assessed in patients of pulmonary tuberculosis and healthy contacts. The studies were based on lymphocyte transformation test and detection of intracellular IFN-γ production by CD4 + ve T-cells by flowcytometry. Patients showed lower levels of proliferation, the stimulation index being in the range of 2.17 1.1 (mean + SD) compared to the contacts (SI = 4 59±1.6) (P < 0.01). The kinetics of intracellular induction of IFN-γ on M. tb. stimulation showed a proportional increase in the CD4 + ve T-cell population. The increase was maximal between 96–120 h of culture. In healthy contacts the number of IFN-γ expressing CD + ve T-cells increased to 2.5 to 41 × 10⁴ cells/ml in M. tb. stimulated cultures compared to control cultures (0.1 – 15 × 10⁴). In contrast patients showed no/marginal increase in CD4 + ve T-cell population expressing intracellular IFN-γ Thus the lack of induction of IFN in CD4 + ve T-cells in patients could be a critical shortcoming in their ability to combat tubercle bacilli infection.     

Changing of Val47 to Asp47 or to Lys47 enhances the immunomodulatory activity of the human Interleukin-l peptide 47–55

The 47–55 domain of the maturehumanInterleukin-was predicted to be exposed by our computational analysis and confirmed to be so by comparing with X-ray crystallographic as well as nuclear magnetic resonance (NMR) spectroscopic data. Four peptides representing fully or part of this domain with sequences 47–55, 41–61, 45–61 and 50–66 were synthesized and tested for their ability to modulate in vivo, the humoral immune response of Balb/c mice to Shigella dysenteriae 116 kDa antigen(s). The smallest immunomodulatory peptide amongst them was found to be the nonapeptide 47–55. To ascertain the structure-function relationships of this 47–55 peptide, various mutant peptides were synthesized and tested for IL-1β ₂ like activity in vivo. Change of Val⁴⁷ to Asp⁴⁷ or to Lys⁴⁷ enhanced its immunomodulatory activity significantly while the change of Gly⁴⁹ to Asp⁴⁹ or Glu⁵⁰ to Ile⁵⁰ or Asp⁵⁴ to Ile⁵⁴ had no such effect. The peptides 47–55 and its mutants were first tested for their ability to elicit inflammatory response like PGE₂ synthesis by a sensitive radioimmunoassay. The peptides which did not have any inflammatory activity were then tested for their ability to stimulate antigen primed T-cells in vitro in the presence of sub-optimal concentration of the antigen.     

A study on distribution of natural radionuclide polonium-210 in a pond ecosystem

This paper presents the results of an investigation on the distribution of²¹⁰Po in Mutharasanallur pond ecosystem. It has been demonstrated that²¹⁰Po is non-uniformly distributed within the ecosystem. The results of the study show a dissolved²¹⁰Po concentration in pond water of 1 4mBq 1₋₁. The sediment samplso recorded a²¹⁰Po activity of 59 9 Bq kg₋₁. The aquatic organisms showed differential accumulation of the radionuclide with enhanced bioaccumulation in soft tissues and muscle. The²¹⁰Po activity in the biota fell within the range of 1·2–53 3 Bq kg₋₁ (wet wt). The bivalve mussel,Lamellidens marginalis was identified to accumulate higher concentration of²¹⁰Poin soft tissues, suggesting that these organisms could serve as a bio-monitor of²¹⁰Po radionuclide in a freshwater system. The concentration factors of²¹⁰Po for the biotic components ranged from ∼10²–∼10⁴. Analyses of the results indicate that prawn and fish represent an important source of supply of²¹⁰Po to humans via dietary intake. Results of²¹⁰Po activity in the abiotic and biotic components of the pond ecosystem were higher when compared with those of Cauvery river system, the primary water source of the pond.     

Regulation of cellular signals by G-proteins

Extracellular signals are transduced across the cell by the cell surface receptors, with the aid of G-proteins, which act at a critical point of signal transduction and cellular regulation. Structurally, G-proteins are heterotrimeric consisting α, β and γ subunits but in functionally active state they dissociate into α subunit coupled to GTP and as βγ dimer. G-proteins can be broadly divided into two classes based on their sensitivity to pertussis toxin and cholera toxin. Existence of various forms of each of the subunit allows molecular diversity in the subunit species of G-proteins. These subunits interact with a wide range of receptors and effectors, facilitated by post translational modification of their subunits. Different types of G-proteins mediate several signalling events in different parts of the body. This review summarizes the features of (i) structural and functional heterogenity among different subunits of G-proteins, (ii) interaction of G-proteins and their subunits with effectors with specific cases of G-protein mediated signalling in olfaction, phototransduction in the retina, ras andras related transduction and (iii) disease conditions associated with malfunctioning of G-proteins.     

Reproduction of the blacktip sawtail catshark,Galeus sauteri,in the waters off northeastern Taiwan

The reproductive biology of blacktip sawtail catsharks,Galeus sauteri, in northeastern Taiwan waters was investigated. Male catsharks possessed paired testes producing spermatozoa, which were then stored in the epididymides all year round. No spermatophores were observed in the lower ductus deferens. Only the right ovary was functional in females, oogonia being formed in the ovarian cortex and then developing into mature ova. Ova exceeding 17 mm in diameter were ovulated. Pregnant individuals contained one eggcase only, in each side of the uterus. No hatched embryos were observed in such eggcases. The size at which 50% of blacktip sawtail catshark specimens were mature was 410–420 mm and 350–360 mm for females and males, respectively. The species does not have a well-defined reproductive season.     

Evaluating second year cropping on jhum fallows in Mizoram, north-eastern India: Soil fertility

Changes in soil fertility were evaluated on young (6 year) and old (20 year) jhum fields in Mizoram, north-eastern India in response to various operations involved injhum such as slashing and burning of vegetation, cropping period, and intervening fallow period between first and second year cropping. The results demonstrate that the soil is richer in nutrients in old than young field prior to the start of jhum cultivation. Slash burning depletes soil acidity, carbon and nitrogen but elevates phosphorus and cations. Soil fertility declined during first cropping phase, and further declined during second cropping phase. After two cropping years, soil fertility of old field was almost at par with that of young field, signifying that the loss of soil fertility was more in old than young field. A short intervening fallow period between first and second year of cropping did not show any pronounced improvement in soil fertility, though it provided some biomass for second burning. Tilling caused maximum loss to soil fertility. The fertilizer treatments ended with comparable or better soil fertility in comparison to no-treatment plot. There seems to be none of the fertilizer treatments superior over others from the standpoint of ending soil fertility. The unifying conclusions of this series of investigations support the hypothesis that the second year cropping holds promise to reduce the demand for forested land for jhum, and lengthen the jhum cycle substantially.     

Role of temperature in regulation of ovarian cycle in bull frog Rana tigerina

Effect of temperature on the ovarian cycle was studied in R. tigerina by exposing them to (1) constant low (22 degrees C) temperature during preparatory (active vitellogenic growth) phase (March-May) when the mean ambient temperature ranged from 26 degrees-28 degrees C and (2) to constant high (30 degrees +/- 1 degrees C) temperature during postbreeding regression phase (August-November) when the mean ambient temperature ranged from 22 degrees-26 degrees C. The ovaries of initial controls (biopsy samples taken prior to the commencement of the experiment) in March contained only first growth phase (FGP) oocytes with a maximum size range of 361-480 microns in diameter. In the frogs exposed to constant low temperature for 2 months, only 7% of FGP oocytes were recruited to second growth phase (SGP) with a mean largest diameter of 631 microns compared to 31% large SGP oocytes with a mean diameter of 1114 microns in the frogs collected from natural fields. The number of atretic follicles (AF) was lower and fat body weights were significantly higher in low temperature exposed frogs. The exposure of the frogs to constant high temperature during postbreeding months caused an increase in the mean diameter and number of large FGP oocytes, numerical increase in AF and decrease in fat body weights over corresponding controls maintained at room temperature. The pituitary gonadotrophs of these frogs showed stimulatory changes such as increase in cell size and appearance of secretory granules in the cytoplasm. The results suggest that in R. tigerina high temperature stimulates oocyte growth while low temperature retards it.(ABSTRACT TRUNCATED AT 250 WORDS)     

ONIOM DFT/PM3 calculation on the interaction between STI-571 and abelson tyrosine kinase

The ONIOM2 (B3LYP/6–31G (d, p): PM3) and B3LYP/6–31G (d, p) methods were applied to investigate the interaction between STI-571 and abelson tyrosine kinase binding site. The complex of N-[4-methyl-3-(4-pyridin-3-yl-pyrimidin-2-ylamino)- phenyl]-benzamide (part of STI-571) and related 16 amino acid residues were found at B3LYP/6–31G (d, p) level to have hydrogen bonds and π....π stacking interaction, their binding energy via HAF optimization was −20.4 kcal mol⁻¹. The results derived from this study agreed well with the reported observation. Figure Optimized structure of STI-571 and Thr315 in abelson tyrosine kinase based on ONIOM2 method     

Endothelin-1 induced sustained contractions of tracheal smooth muscle involve an activation of protein kinase C

Endothelin-1, a potent vasoconstrictor peptide produces concentration dependent contractions in lamb tracheal smooth muscle. These contractions are not inhibited by low doses (up to 20 μM) of trifluoroperazine and W-7, the calmodulin/myosin light chain kinase (MLCK) inhibitors. At higher concentrations (200 μM), a delayed and poor reversal of isometric tensions results. These relaxations are coupled with a partial dephosphorylation of regulatory myosin light chain (MLC). Preincubation of fiber strips in MLCK inhibitors (200 μM) results in a delayed and attenuated contractile response but without a dephosphorylation of MLC. H-7, a putative protein kinase C antagonist (25–100 μM) abolishes endothelin-1 induced contractile effects rapidly (50% relaxation within 1–3 min). Moreover, such relaxations are accompanied by complete dephosphorylation of MLC. Phorbol 12, 13-dibutyrate, an exogenous activator of protein kinase C potentiates the endothelin induced contractions. Inactive phorbol ester, 4α-phorbol ester does not elicit any contractile response in the muscle. The down regulation of protein kinase C, on the other hand suppresses such potentiated contractile responses. These results suggest that endothelin-1 induced contractile tensions in tracheal smooth muscle are mediated by a mechanism that involves an activation of enzyme protein kinase C.     

Diplectrum radiale (Quoy & Gaimard, 1824) (Serranidae): A rare case of simultaneous hermaphroditism in a teleost fish

This study generates, for the first time, information on the reproductive traits of the simultaneous hermaphrodite Diplectrum radiale. The specimens were captured bimonthly in two distinct ecosystems along the south‐eastern Brazilian coast. The mature ovotestes were removed, preserved in formalin and examined using histological techniques. The results revealed indeterminate fecundity with asynchronous ovarian organization. All spermatogenesis occurs within cysts, and the spermatogonial distribution indicated an unrestricted testicular type. The testicular and ovarian tissues were separated from each other by different ducts, indicating no possibility of internal self‐fertilization. The hydrated oocytes were stored in the accessory reproductive structure for at least 24 hr. The presence of atretic hydrated oocytes within this structure and the positive periodic acid–Schiff reaction of the villi‐like projections revealed the function of the ovary sinus as absorbing unspawned oocytes. The relative batch fecundity ranged from 62 to 209 oocytes/g (126 ± 42) for specimens from the coast and from 52 to 203 oocytes/g (113 ± 57) for those sampled in the estuary. The potential batch fecundity was linearly related to size, weight, and the gonadosomatic and hepatosomatic indices, revealing that these parameters significantly affect the reproductive potential of D. radiale.     

Molecular Coordinated Regulation of Gene Expression During Ovarian Development in the Penaeid Shrimp

To understand the molecular events of ovarian development in penaeid shrimp, RNA arbitrarily primed polymerase chain reaction (RAP-PCR) was used to identify differentially expressed genes during ovarian maturation in Metapenaeus ensis. From a screening of 700 clones in a cDNA library of the shrimp ovary by the products of RAP-PCR of different maturation stages, 91 fragments with differentially expressed pattern as revealed by dot-blot hybridization were isolated and sequenced. Forty-two of these fragments show significant sequence similarity to known gene products and the differentially expressed pattern of 10 putative genes were further characterized via Northern hybridization. Putative glyceraldehyde–3–phosphate dehydrogenase and arginine kinase are related to provision of energy for active cellular function in oocyte development. Translationally controlled tumor protein, actin, and keratin are related to the organization of cytoskeleton to accomplish growth and development of oocytes. High mobility group protein DSP1, heat shock protein 70, and nucleoside diphosphate kinase may act as repressors before the onset of ovarian maturation. Peptidyl-prolyl cis-trans isomerase and glutathione peroxidase are related to the stabilization of proteins and oocytes. This study provides new insights on the molecular events in the ovarian development in the shrimp. Present addresses: T.S. Lo, Department of Applied Science, Hong Kong Institute of Vocational Education, Chai Wan, Hong Kong, China J.L.Y. Mong, Department of Biochemistry, The Chinese University of Hong Kong, Shatin, Hong Kong, China Q.W.L. Wong, Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Shatin, Hong Kong, China     

Characterization of the 90 kDa heat shock protein (HSP90)-associated ATP/GTPase

The 90 kDa heat shock protein (HSP90) is an ATP-binding molecular chaperone with an associated ATPase activity having nucleoplasmin and HSP70-binding homology domains and containing Ca-binding EF-hands and a nuclear localization signal. Here we characterize the HSP90-associated ATPase and show that it is (i) a P-type ATPase inhibited by molybdate and vanadate, (ii) able to hydrolyze methylfluorescein phosphate with a 5–6-fold higher affinity, (iii) a 3-times better GTPase than ATPase in the presence of calcium and (iv) HSP27 and F-actin, but not HSP10 can “convert” the HSP90-associated ATPase activity to HSP90 autokinase activity. The HSP90-associated ATP/GTPase may participate in the regulation of complex formation of HSP90 with other proteins, such as F-actin, tubulin and heat shock proteins.     

Quantitative study of cellular and volumetric growth of magnocellular and laminar auditory nuclei in developing chick brainstem

Development of the second and third order auditory nuclei—nucleus magnoscellularis (NM) and nucleus laminaris (NL) respectively—was studied using Nissl stained serial sections from brain specimens between 8 day of incubation and posthatch day 1, at every two day interval. Reconstruction of these nuclei from three incubation ages showed progressive growth of both nuclei in a rostrocaudal direction. The volume, total neuron, dead cell and glial cell numbers were estimated using stereological quantitation methods. Both nuclei, while undergoing an overall gradual increase in volume up to 20 days registered a transient drop in volume; earlier for NM at 10 days and later for NL at 18 days. From day 20 the two nuclei showed accelerated growth in volume. The total neuron count rapidly declined up to 12 days with 43% loss of neurons in NM followed by a rise and later stabilization within a certain range. The NL, however, showed a continuous fall in neuron numbers throughout the incubation period with 20% cell loss by day 12 and an overall loss of 52%. Cell death in both nuclei was maximal at 16 days and spanned the entire period of incubation. Glia showed a biphasic increase with peak at 14 days for both NM and NL followed by a subsequent rise at day 20 for both nuclei. These data would help in planning further experimental studies of auditory manipulation.     

Major histocompatibility complex restriction in tuberculosis susceptibility

More than one mechanism may contribute to disease susceptibility in tuberculosis, viz., major histocompatability complex (MHC) restriction phenomenon, spectrum of immune reactivity/cytokine profile and epidemiology induced anergy. Experiments from our laboratories revealed that (i) human leucocyte antigen D-related allele 2 (HLA DR2) predispose for a more severe form of pulmonary tuberculosis encoding a high responder status, (ii) spectrum of immune reactivity to mycobacteria is ‘innate’, and it is demonstrable in healthy individuals from endemic area, (iii) there is no correlation between the purified protein derivative (PPD) response and peptide responses, (iv) once a person is high responder to P16 and P38 derived peptides (6/22), he/she (whether a patient or control) is a high responder for a wide range of mycobacterial peptides and (v)majority of the T-cell clones generated in vitro, to peptide 16.3 (amino acids 21–40) of 16 kA a mycobacterial antigen, in an HLA DR2 positive healthy individual is HLA DR restricted, permissive and of Th1 phenotype. The results suggested that MHC class II restriction play a role in peptide recognition and the immune response. Nonetheless the outcome and specificity of the immune reactivity and the resultant disease pathogenesis may depend on the promiscuity of peptide recognition and cytokine profiles.