Two distinct but distantly related complementary DNAs encoding proteins sharing human interleukin-1 (IL-1) activity (termed IL-1 alpha and IL-1 beta), were isolated from a macrophage cDNA library. The primary translation products of the genes are 271 and 269 amino acids long, although expression in Escherichia coli of the carboxy-terminal 159 and 153 amino acids produces IL-1 biological activity.

Interleukin-1 beta (IL-1 beta) mediates a wide range of immune and inflammatory responses. The active cytokine is generated by proteolytic cleavage of an inactive precursor. A complementary DNA encoding a protease that carries out this cleavage has been cloned. Recombinant expression in COS-7 cells enabled the cells to process precursor IL-1 beta to the mature form. Sequence analysis indicated that the enzyme itself may undergo proteolytic processing. The gene encoding the protease was mapped to chromosomal band 11q23, a site frequently involved in rearrangement in human cancers.

Leukemia inhibitory factor (LIF) and interleukin-6 (IL-6) are multifunctional cytokines with many similar activities. LIF is structurally and functionally related to another cytokine, Oncostatin M (OSM), that binds to the high-affinity LIF receptor but not to the low-affinity LIF receptor. A complementary DNA was isolated that encodes the high-affinity converting subunit of the LIF receptor. The converter conferred high-affinity binding of both LIF and OSM when expressed with the low-affinity LIF receptor and is identical to the signal transducing subunit of the IL-6 receptor, gp130. The gp130 subunit alone confers low-affinity binding of OSM when expressed in COS-7 cells. This receptor system resembles the high-affinity receptors for granulocyte-macrophage colony-stimulating factor, IL-3, and IL-5, which share a common subunit.

The events involved in the commitment and development of lymphoid lineage cells are poorly understood. We have used a recently described long-term culture system to establish a bioassay that can detect a novel growth factor capable of stimulating the proliferation of lymphoid progenitors. Using direct expression in mammalian cells we have isolated a complementary DNA clone encoding this novel haematopoietic growth factor, designated interleukin-7.

cDNA clones corresponding to an Mr approximately 80,000 receptor (type I receptor) for interleukin‐1 (IL‐1) have been isolated previously by mammalian expression. Here, we report the use of an improved expression cloning method to isolate human and murine cDNA clones encoding a second type (Mr approximately 60,000) of IL‐1 receptor (type II receptor). The mature type II IL‐1 receptor consists of (i) a ligand binding portion comprised of three immunoglobulin‐like domains; (ii) a single transmembrane region; and (iii) a short cytoplasmic domain of 29 amino acids. This last contrasts with the approximately 215 amino acid cytoplasmic domain of the type I receptor, and suggests that the two IL‐1 receptors may interact with different signal transduction pathways. The type II receptor is expressed in a number of different tissues, including both B and T lymphocytes, and can be induced in several cell types by treatment with phorbol ester. Both IL‐1 receptors appear to be well conserved in evolution, and map to the same chromosomal location. Like the type I receptor, the human type II IL‐1 receptor can bind all three forms of IL‐1 (IL‐1 alpha, IL‐1 beta and IL‐1ra). Vaccinia virus contains an open reading frame bearing strong resemblance to the type II IL‐1 receptor.