Antarctic Fish Immunoglobulins: Preliminary Data on
Structure and Antibody Specificity
Maria Rosaria Coscia and Umberto Oreste
Institute of Protein Biochemistry and Enzymology, CNR, Via Marconi 12, 80125
Naples, Italy
Fish immunoglobulins resemble mammalian IgM in terms of size (five Ig
domains), carbohydrate composition of the heavy chain (12-16%), and
polymeric assembly of the basic unit H2L2 (tetrameric in bony fish and
pentameric in cartilaginous fish). However, the overall features of the
mammalian secondary immune response (rise in titre, shift to high affinity
antibodies, isotypic switch) are not found in fish [1].
For an adequate understanding of fish immunity, many groups have
focused their research efforts on the Ig gene structure: in particular,
regarding teleosts, the organisation of H chain genes is shown to be of
mammalian type, whereas that ofL chain genes is of multi cluster type [2].
Little is known about the VH diversity. Several teleost species are known
to have multiple Ig VH families [3-5].
We think that studying the Antarctic fish Ig is a suitable approach to
learn more about the functional adaptation of Ig to particularly extreme
environmental conditions. In fact it is known that cold temperatures tend to
depress life functions including the immune response.
We have dealt with the isolation and characterization of Ig from a
number of Antarctic fish species. We purified Ig from plasma of
Trematomus bernacchii, Notothenia coriiceps, Chaenocephalus aceratus,
Chionodraco hamatus, from eggs of C. hamatus, from bile of T bernacchii
and from cutaneous mucus of Gobionotothen gibberifrons [6,7]. The
purification procedure used was a combination of thiophilic adsorption
chromatography on T -gel and size exclusion fast performance liquid
chromatography (FPLC) on Superose 6 column. We found the T-gel
chromatography as an efficient alternative to other Ig purification methods,
such as the ammonium sulfate precipitation, anion exchange
chromatography or Protein A Sepharose CL-4B affinity chromatography,
which yielded lower amounts of purified fish Ig.
The Igltotal protein ratio was found lower for the bile compared with the
other samples analyzed [6]. The plasma or bile fractions bound by T-gel
were analyzed in FPLC (Fig. 1A). The relative molecular mass of the
major peak (780 kDa) of plasma Ig was interpreted to correspond to the
tetrameric assembly (Fig. lB). Indeed, the FPLC elution profile of bile Ig
G. di Prisco, E. Pisano, A. Clarke (Eds)
Fishes of Antarctica. A biological overview
© Springer-Verlag Italia 1998
Structure and Antibody Specificity
Maria Rosaria Coscia and Umberto Oreste
Institute of Protein Biochemistry and Enzymology, CNR, Via Marconi 12, 80125
Naples, Italy
Fish immunoglobulins resemble mammalian IgM in terms of size (five Ig
domains), carbohydrate composition of the heavy chain (12-16%), and
polymeric assembly of the basic unit H2L2 (tetrameric in bony fish and
pentameric in cartilaginous fish). However, the overall features of the
mammalian secondary immune response (rise in titre, shift to high affinity
antibodies, isotypic switch) are not found in fish [1].
For an adequate understanding of fish immunity, many groups have
focused their research efforts on the Ig gene structure: in particular,
regarding teleosts, the organisation of H chain genes is shown to be of
mammalian type, whereas that ofL chain genes is of multi cluster type [2].
Little is known about the VH diversity. Several teleost species are known
to have multiple Ig VH families [3-5].
We think that studying the Antarctic fish Ig is a suitable approach to
learn more about the functional adaptation of Ig to particularly extreme
environmental conditions. In fact it is known that cold temperatures tend to
depress life functions including the immune response.
We have dealt with the isolation and characterization of Ig from a
number of Antarctic fish species. We purified Ig from plasma of
Trematomus bernacchii, Notothenia coriiceps, Chaenocephalus aceratus,
Chionodraco hamatus, from eggs of C. hamatus, from bile of T bernacchii
and from cutaneous mucus of Gobionotothen gibberifrons [6,7]. The
purification procedure used was a combination of thiophilic adsorption
chromatography on T -gel and size exclusion fast performance liquid
chromatography (FPLC) on Superose 6 column. We found the T-gel
chromatography as an efficient alternative to other Ig purification methods,
such as the ammonium sulfate precipitation, anion exchange
chromatography or Protein A Sepharose CL-4B affinity chromatography,
which yielded lower amounts of purified fish Ig.
The Igltotal protein ratio was found lower for the bile compared with the
other samples analyzed [6]. The plasma or bile fractions bound by T-gel
were analyzed in FPLC (Fig. 1A). The relative molecular mass of the
major peak (780 kDa) of plasma Ig was interpreted to correspond to the
tetrameric assembly (Fig. lB). Indeed, the FPLC elution profile of bile Ig
G. di Prisco, E. Pisano, A. Clarke (Eds)
Fishes of Antarctica. A biological overview
© Springer-Verlag Italia 1998